Websense is a San Diego-based company specializing in computer security software, which is used by customers including businesses, schools, and libraries, to protect their networks from malware, stop data theft, prevent students from viewing sexual or other inappropriate content, and discourage employees from spending time browsing non business-related websites. Websense uses a combination of classification engines, filtering categories, data fingerprints and word filters designated by a company’s network administrator policy.

In the past, these policies have been criticized because it can block innocent websites or content protected by free speech, like sexual educationwebsites. This can be done on purpose as internet censorship, or simply by accident due to over-reaching categories. This has led some to call it "censorware". While countries have used it for country-wide blocking of ideologies that the government disapproves of, Websense expressly prohibits using their software in this manner.The company also allows the public to ask for security details and categorization, or request a re-categorization through email. 

History
Websense was founded by Phil Trubey in 1994, and went public in the year 2000. According to Gartner the company is one of the five companies leading theSecure Web Gateway (SWG) market.

Apart from web filtering, the company provides software-based, appliance-based and cloud-based email security, and data loss-prevention technology. The software also tracks individual internet usage for the purpose of collecting and reporting on any browsing deviating from the standards set by the library, government or other employer, and its reports can be data drilled by "risk class, category, URL, application, user, workstation, dates, and more."

Products through acquisition
UK company SurfControl was acquired by Websense on October 3, 2007. Websense has indicated it will continue the Surfcontrol business with a full staff until at least 2011

Websense's proprietary "Deep Content Control" is software designed to protect confidential information. The company says it is a combination of its ThreatSeeker and PreciseID technologies.PreciseID uses software first developed for the Israeli military. The company has a Data Loss Prevention product called Information Leak Prevention, which was developed by the Israel-based data security company PortAuthority Technologies. In December 2006 Websense bought PortAuthority for $90 million. Announcing the take-over, Websense said that it was "committed to maintaining the company's research and development presence in Israel."

On January 27, 2009, Websense acquired Defensio, a security company specialized in blog plugins that help to fight spam and malicious links in the comment sections of blogs. This will help expand its ThreatSeeker Network and could be used by webmasters to warn as soon as suspicious content is posted to their websites.

Partnership with Facebook
On October 3, 2011, Facebook and Websense announced a partnership in order to protect its users from dangerous links that lead to malicious websites and malware sites. According to TechCrunch, “Going forward, when a Facebook user clicks on a link, the new system will first check the link against Websense’s system to determine whether or not it’s safe. If it’s not, a message is displayed warning the user that the link is potentially harmful and suggests you return to the previous page.”

Takeover target
In March 2012, Bloomberg reported that Websense was the target of a takeover bid by Quest Software.

Web filtering software

Websense blocking a website because the administrator has restricted access to category "Tasteless".

Websense may be implemented as a software application, computer appliance or cloud-based service operating at the transport layer as a transparent proxy, or at the application layer as a web proxy. In each scenario, the effect is that it can inspect and filter network traffic to or from the internet for a target group of people.

Websense allows system administrators to block access to web sites and other protocols based on categories. These contain lists of sites that may be blocked at will, either at specified times or permanently. This can result in considerable variance in the selection of categories to filter: for example, a 2008 study on the use of Websense within the Technical Colleges of Georgia found that only two categories were blocked in all of the colleges surveyed, and that 39 categories out of the 43 listed were blocked by some, but not all, colleges, with numbers ranging from two colleges blocking a given category to 23 out of the 24 respondents. The software offers clients an optional continue button which permits users to access an otherwise blocked category if it is work related.

The ability for public libraries, governments or other employers to block content based on ideology has proved controversial due to the subjects being blocked being controlled by an individual organization or even a single individual. The blocking of sites can exceed that which is required by bodies responsible for the oversight of these institutions, and, in the case of educational institutions, criticism has been leveled at the decision making process. Due to these problems, it's sometimes referred to as "censorware"
Policies can be produced that control either previously identified information that contains 'tags' such as account numbers, credit card records or any combination of many variables. A score is assigned based on a pre defined set of rules and an action applied. The process can be entirely automated but relies upon either pre set policy templates or bespoke rule sets that are developed in house.

In companies, it can prevent the access to sites known to be infected with spyware and other malicious content, it can prevent malicious programs from connecting to outside sites, and it can limit the amount of bandwidth used by individual computers in a network. The mere knowledge that web access is controlled can cause employees to stop using Internet during work hours for personal purposes, out of fear (that they may be caught misusing Internet).

Blocking errors
On occasion, Websense's filter has categorized notable sites in error. In 2007 Norman Finkelstein and Noam Chomsky[citation needed]'s websites were blocked by network administrators blocking the 'racism/hate speech' category for approximately 24 hours until Finkelstein complained. For approximately 24 hours in 2009, Websense classified router company Cisco's website under 'hack sites'. Websense has a submission form on the website to report mistaken categorization, although it is only available with an account.
In a 2005 report the Rhode Island branch of the American Civil Liberties Union called Websense a deeply flawed technology. It further notes that, although the blocking technology has improved over the years since 2002, it still remains a "blunt instrument" and that in public libraries equipped with Websense people of all ages "are still denied access to a wide range of legitimate material." 

A 2006 report by Brennan Center for Justice says that web filtering programs used in schools were error-prone. For Websense, it discovered that a page discussing pornographic content had been blocked despite not containing any pornography, and a whole website had been blocked because one of its pages had sexual content.

In 2011 it was reported by a blogger that Websense would block pages that contained pornographic links anywhere in its content, even in the comments section; "a malicious attacker could get your whole site blocked at any time by the simple procedure of leaving dangerous, malicious or pornographic links in a blog's comments".

The blocking categories can contain errors, and blocking of certain categories can be used, accidentally or on purpose, to prevent people from seeing legitimate content. For example, Websense categories include, amongst others, the following: "Professional and Worker Organizations", "Social and Affiliation Organizations", "Political Organizations", "Advocacy Groups", "Gay or Lesbianor Bisexual Interest", "Sex education", "Traditional Religions" and "Non-traditional Religions and Occult and Folklore". In response to a complaint from the American Civil Liberties Union in 2011, Websense clarified its definition of the "Gay or Lesbian or Bisexual Interest" category, after it became apparent that some administrators mistakenly believed that this category had to be enabled to ensure that sexually explicit websites were blocked in schools.

A comparative study was made in 2002, to study how the blocking of pornography websites affected the search of legitimate health-related information. When configured at the least-restrictive settings (only blocking sites in the category of pornography), all blocking software blocked the least number of health-related sites, and blocked most of the pornography. As they tested more restrictive settings, the health-related searches were considerably impeded, and the efficiency of blocking pornographic websites increased only marginally. Websense had similar results to the other programs.

Usage by governments
See also: Internet censorship
In 2004 Amnesty International listed Websense as one of several foreign companies that had reportedly provided technology that was used to censor and control the use of the Internet in China.

The OpenNet Initiative reported in 2004 that Websense technology was used by the government in Yemen to enforce censorship of the Internet. In 2008 it was denounced again by the Yemen Times. The company has a policy of not doing business with governments that force censorship of the Internet or oppress rights. The only exceptions are for preventing minors from watching adult content and for child pornography. In 2009 it issued a statement about how it was discontinuing the database downloads to the Yemeni ISP, due to the violation of its stated policy. but reporters from ONI infer that Websense software was still being used by Yemen’s ISP, YemenNet, to censor Internet access as late as August 2010. Websense was finally discontinued in Yemen sometime around January 2011  and apparently it is no longer being used in any Middle East or North Africa country.

On November 1, 2011, Websense General Counsel, Michael Newman, released a public letter to “challenge all other American technology vendors to join us in prohibiting repressive regimes from using American technology to prevent open communications.” The letter’s call for action included, “If you are an executive at a security company that makes software that can be used to censor Internet activity in repressive regimes, we ask that you support the right course of action and stop selling repressive tools to oppressive regimes.” The company joined the Global Network Initiative the same year.

In response, the Electronic Frontier Foundation (EFF) noted, “Websense is pointing the technology sector in the direction of promoting freedom; BlueCoat represents the aiding oppressors. The choice for other tech companies is clear, and kudos to Websense for leading the way.” In March 2012, the EFF also praised Websense for denouncing Pakistan's censorship plans.