Pinterest is a pinboard-style photo-sharing website that allows users to create and manage theme-based image collections such as events, interests, and hobbies. Users can browse other pinboards for images, 're-pin' images to their own pinboards, or 'like' photos. The site was founded by Ben Silbermann, Paul Sciarra and Evan Sharp, the site is managed by Cold Brew Labs and funded by a small group of entrepreneurs and inventors.

Pinterest is similar to earlier social image bookmarking systems based on the same principle, such as David Galbraith's 2005 project Wists.It allows users to save images and categorize them on different boards. They can follow other users' boards if they have similar tastes. Popular categories are travel, cars, food, film, humor, home design, sports, fashion, and art.
Development of Pinterest began in December 2009, and the site launched as a closed beta in March 2010. The site proceeded to operate in invitation-only open beta.

Silbermann said he personally wrote to the site's first 5,000 users offering his personal phone number and even meeting with some of its users.

Nine months after launch the website had 10,000 users. Silbermann and a few programmers operated the site out of a small apartment until the summer of 2011
Early in 2010, the company's investors and co-founder Ben Silbermann tried to interest a New York-based magazine publishing company in buying Pinterest. The publisher declined to meet with the founders.

The launch of an iPhone app in early March 2011 brought in a more than expected number of downloads.

On 16 August 2011, Time magazine listed Pinterest in its 50 Best Websites of 2011 article. 

The Pinterest app for iPhone was last updated in March 2013,   and the iPad app was launched August 2011.   Pinterest Mobile, launched September 2011, is a version of the website for non-iPhone users. 

In December 2011, the site became one of the top 10 largest social network services, according to Hitwise data, with 11 million total visits per week.   The next month, it drove more referral traffic to retailers than LinkedIn, YouTube, and Google+.
The same month, the company was named the best new startup of 2011 by TechCrunch.   Noted entrepreneurs and investors include Jack Abraham, Michael Birch, Scott Belsky, Brian Cohen, Shana Fisher, Ron Conway, FirstMark Capital, Kevin Hartz, Jeremy Stoppelman, Hank Vigil, and Fritz Lanman. 

In January 2012, comScore reported the site had 11.7 million unique users, making it the fastest site in history to break through the 10 million unique visitor mark.   Pinterest's wide reach helped it achieve an average of 11 million visits each week in December 2011. Most of the site's users are female.
At the South By Southwest Interactive conference in March 2012, Silbermann announced revamped profile pages were being developed and would be implemented soon. 

On 23 March 2012, Pinterest unveiled updated terms of service that eliminated the policy that gave it the right to sell its users' content.   The terms would go into effect April 6. 

According to Experian Hitwise, the site became the third largest social network in the United States in March 2012, behind Facebook and Twitter. 

Co-founder Paul Sciarra left his position at Pinterest in April 2012 for a consulting job as entrepreneur in residence at Andreessen Horowitz.
 
On 17 May 2012, Japanese electronic commerce company Rakuten announced it was leading a $100 million investment in Pinterest, alongside investors including Andreessen Horowitz, Bessemer Venture Partners, and FirstMark Capital, based on a valuation of $1.5 billion. 
 
On 10 August 2012, Pinterest no longer required a request or an invitation to join the site.   In addition, the Pinterest app for Android and iPad was also launched on August 14, 2012.   The Android app was customer designed for Android phones & tablets of all cost, speed and size while the iPad app is described as the best Pinterest experience yet. 

On September 20, 2012 Pinterest announced hiring its new head of engineering, Jon Jenkins. Jenkins came from Amazon, where he spent eight years as an engineering lead and was also a director of develop tools, director of platform analysis and director of website platform. 

In October 2012, Pinterest announced a new feature that would allow users to report others for negative and offensive activity or block other users if they do not want to view their content. Pinterest said they want to keep their community positive and respectful. Also in October, Pinterest launched business accounts allowing businesses to either convert their existing personal accounts into business accounts, or start from scratch.
 
In March 2013, Pinterest acquired Livestar. Terms were not disclosed. 
Pinterest users can upload, save, sort and manage images, known as pins, and other media content (e.g. videos) through collections known as pinboards.   Pinterest acts as a personalized media platform, whereby users' content and the content of others can be browsed on the main page. Users can then save individual pins to one of their own boards using the Pin It button, with Pinboards typically organized by a central topic or theme. Content can also be found outside of Pinterest and similarly uploaded to a board via the Pin It button which can be downloaded to the bookmark bar on a web browser,   or be implemented by a webmaster directly on the website.

There are several ways to register a new Pinterest account. Potential users can either receive an invitation from a friend already registered. Alternatively they could request an invitation directly from the Pinterest website, however, this may take some time to be received. An account can also be created and accessed by linking Pinterest to a Facebook or Twitter profile. When a user re-posts or re-pins an image to their own board, they have the option of notifying their Facebook and Twitter followers; this feature can be managed on the settings page.   Users who choose to log into Pinterest via Facebook must currently be using Facebook's Timeline format. 
 
On the main Pinterest page, a pin feed appears, displaying the chronological activity from the Pinterest boards that a user follows.   When browsing for new boards and relevant pins, users can visit a Tastemakers page that recommend pinboards with content similar to previous pins saved by a user.   For both guests and Pinterest users, there are currently four main sections to browse everything, videos, popular, and gifts. These subcategories provide an organized system of browsing, helping fellow users to connect and share interests.
Quick links to Pinterest include the pin it button that can be added to the bookmark bar of a web browser, Follow me and Pin it buttons added to personal website or blog page,   and the Pinterest iPhone application available (for free) through the App Store. 

Users should be aware of certain terms and functions when using Pinterest. A board is where the users pins are located, users can have several boards for various items. A pin is an image that has either been uploaded or from a link on a website. Once users create boards and add pins, other users can now repin meaning that they can pin one users image to their board as well.   Once the user has set up their account and boards, they can browse, comment, and like other pins. If a user wants to turn an image online into a pin there are a few simple steps to do so. First, the user must select image that you want to pin. Second, the user then click on the “Add +” button on Pinterest. Third, copy and paste an image URL into the link box. Next, the user will select the exact image they wish to pin and place in the designated board. Users can then describe the pin and share it via Twitter or Facebook. Other users can now click on the pin to see which board the image is pinned in, who pinned the image previously, where the original pin is from, and who has liked, commented, or repinned the image.

The website has proven especially popular among women.   The most popular categories on Pinterest are food & drink, DIY & crafts, women's apparel, home decor, and travel. 

Pinboards can be used by educators to plan lessons. Teachers can pin sites for later referral. Students can pin and organize sources and collaborate on projects. 

Pinterest has played a role in the run-up to the 2012 US Presidential Election. The wives of both candidates created accounts. Ann Romney debuted her Pinterest account in March and First Lady Michelle Obama announced hers in June. 

Business pages
Pinterest also allows businesses to create pages aimed at promoting their businesses online.   Such pages can serve as a virtual storefront.   In one case study of a fashion website, users visiting from Pinterest spent $180 compared with $85 spent from users coming from Facebook. These users spent less time on the company's website, choosing instead to browse from the company's pinboard.   Further brand studies have continued to show Pinterest is more effective at driving sales than other forms of social media. 

User base
Globally, the site is most popular with women. In 2012, it was reported that 83% of the global users were women.   In Britain, however as of March 2012, 56% of the users were male and their age profile was different too, being about 10 years younger than in the U.S., where the age range was typically 35-44.   In terms of age distribution, the Pinterest demographic closely resembles the U.S. Internet population. 

Growth
For January 2012, comScore reported the site had 11.7 million unique U.S. visitors, making it the fastest site ever to break through the 10 million unique visitor mark.   comScore recorded a unique users moving average growth of 85% from mid-January to mid-February and a 17% growth from mid-February to mid-March. 

Much of the service's early user base consisted of infrequent contributors. The site's user growth, which slowed in March 2012, could pick up as the site's user base solidifies around dedicated users according to a comScore representative.   In August 2012, Pinterest overtook competing micro-blogging site Tumblr for the first time in terms of unique monthly visitors, clocking in at just under 25 million.
 
In February 2013, Reuters and ComScore stated that Pinterest had 48.7 million users.
 
Business
Pinterest was first conceptualized in December 2009 by co-founders Ben Silbermann, Evan Sharp and Paul Sciarra. The first prototype was launched in March 2010 where it was available to a small group of colleagues and family members.   Since its inception three years ago, it has developed into a well-funded site financially supported by a group of successful entrepreneurs and investors including FirstMark Capital, Jack Abraham (Milo), Michael Birch (Bebo), Scott Belsky (Behance), Shana Fisher (Highline Venture Partners), Ron Conway (SV Angel), Kevin Hartz (EventBrite), Jeremy Stoppelman (Yelp), Hank Vigil, Fritz Lanman, and Brian S. Cohen.   As Pinterest continues to grow and develop, so does its business opportunity as a promising marketing platform, especially in terms of data collection for retail companies and marketing strategists

In early 2011, the company secured a $10 million USD Series A financing led by Jeremy Levine and Sarah Tavel of Bessemer Venture Partners. In October 2011, after an introduction from Kevin Hartz and Jeremy Stoppelman, the company secured $27 million USD in funding from Andreessen Horowitz, which valued the company at $200 million USD.
 
Retail companies have taken advantage of Pinterest for advertising and style trending. The web design provides an ideal layout for style conscious retailers, where products can easily be visualized within a consumer context. Companies like The Gap, Chobani, Nordstrom and West Elm use Pinterest as a tool for online referrals that link users with similar interests to a company.The Gap has arguably taken the biggest initiative in their use of Pinterest, employing their own themed pinboards such as Denim Icons and Everybody in Gap.
 
Baynote founder Scott Brave sees Pinterest as an ideal environment to collect affinity data; a resource that holds the potential for substantial demand and income. This data reveals valuable relationships between consumer behaviours, products and content, where it can be collected and sold as marketing analysis. 
In May 2012, Pinterest was valued at $1.5 billion.In February 2013, it was valued at $2.5 billion. 

Copyrighted content
Pinterest has a notification system which allows copyright holders to request that content be removed from the site. The Digital Millennium Copyright Act (DMCA) safe harbor status of Pinterest has been questioned given that it actively promotes its users to copy to Pinterest, for their perpetual use, any image on the Internet. Pinterest users cannot claim safe harbor status and as such are exposed to possible legal action for pinning copyrighted material.
 
A nopin HTML meta tag was released by Pinterest on 20 February 2012 to allow websites to opt out of their images being pinned. On 24 February 2012, Flickr implemented the code to allow users to opt out their photos.
 
Pinterest released a statement in March 2012 saying it believed it was protected by the DMCA's safe harbor provisions.No major copyright lawsuits have emerged as of March 2012. 

In early May 2012, the site added automatic attribution of authors on images originating from Flickr, Behance, YouTube and Vimeo. Automatic attribution was also added for Pins from sites mirroring content on Flickr. At the same time Flickr added a Pin shortcut to its share option menu to users who have not opted out of sharing their images. 

Reception
Terms of service
A Scientific American article criticized Pinterest's self-imposed ownership of user content stating that Pinterest's terms of service have been garnering a lot of criticism for stating in no uncertain terms that anything you pin to their site belongs to them. Completely. Wholly. Forever and for always. At the time, Pinterest's terms of service stated that By making available any Member Content through the Site, Application or Services, you hereby grant to Cold Brew Labs a worldwide, irrevocable, perpetual, non-exclusive, transferable, royalty-free license, with the right to sublicense, to use, copy, adapt, modify, distribute, license, sell, transfer, publicly display, publicly perform, transmit, stream, broadcast, access, view, and otherwise exploit such Member Content only on, through or by means of the Site, Application or Services.   Under these terms all personal, creative and intellectual property posted to the site belonged to the website and could be sold. A Scientific American blogger pointed out that this contradicted another line in the terms of service, that Cold Brew Labs does not claim any ownership rights in any such Member Content. 

In March 2012, Pinterest unveiled updated terms of service that ended the site's claims of ownership once implemented in April. Selling content was never our intention, said the company in a blog post.   

Legal status
In February 2012, photographer and lawyer Kirsten Kowalski wrote a blog post explaining how her interpretation of copyright law led her to delete all her infringing pins.   The post contributed to scrutiny over Pinterest's legal status.   The post went viral and reached founder Ben Silbermann who contacted Kowalski to discuss making the website more compliant with the law.
 
Content creators on sites such as iStock have expressed concern over their work being reused on Pinterest without permission. Getty Images said that it was aware of Pinterest's copyright issues and was in discussion with them.
A meta tag was released by Pinterest in February 2012 to allow websites to opt out of their images being pinned. 

At the 2012 Webby Awards, Pinterest won best social media app and people's voice award for best functioning visual design. 

Many third-party developers have created web applications, browser extensions, and even podcasts devoted to Pinterest. These items range from analytics, to enlarging the images on Pinterest's website.

Pinterest is written on the Django python web framework.

Use by scammers
Social engineering of Pinterest users by scammers to propagate surveys promising free products was noted by the computer security firm Symantec in March 2012. Scam images, often branded with a well-known company name like Starbucks, offer incentives such as gift cards for completing a survey. Once the link in the description is clicked, users are taken to an external site and asked to re-pin the scam image. Victims are phished for their personal information and the promised free product is never delivered.

Other scammers capitalized on the lack of an official Google Play app. Low-quality Pinterest apps purporting to be official have appeared that generate ad revenue or monitor the downloader's activity. There is now an official Pinterest app for Android devices.