Chapter 15 Unified Threat Management for FortiOS 5.0 : Security Profiles overview : Security Profiles components : Web filtering
  
Web filtering
Web filtering includes a number of features you can use to protect or limit your users’ activity on the web.
FortiGuard Web Filtering is a subscription service that allows you to limit access to web sites. More than 60 million web sites and two billion web pages are rated by category. You can choose to allow or block each of the 77 categories.
URL filtering can block your network users from access to URLs that you specify.
Web content filtering can restrict access to web pages based on words and phrases appearing on the web page itself. You can build lists of words and phrases, each with a score. When a web content list is selected in a web filter profile, you can specify a threshold. If a user attempts to load a web page and the score of the words on the page exceeds the threshold, the web page is blocked.