Commercially available products that can be configured to block or filter access to certain material on the Internet are among the “technology protection measures” that may be used to attempt to comply with CIPA.  There are numerous filtering software products available commercially.  Three network-based filtering products – SurfControl’s Cyber Patrol, N2H2’s Bess/i2100, and Secure Computing’s SmartFilter – currently have the lion’s share of the public library market.  The parties in this case deposed representatives from these three companies.  Websense, another network-based blocking product, is also currently used in the public library market, and was discussed at trial.  Filtering software may be installed either on an individual computer or on a computer network.  Network-based filtering software products are designed for use on a network of computers and funnel requests for Internet content through a centralized network device.  Of the various commercially available blocking products, network-based products are the ones generally marketed to institutions, such as public libraries, that provide Internet access through multiple terminals.  Filtering programs function in a fairly simple way.  When an Internet user requests access to a certain Web site or page, either by entering a domain name or Ip address into a Web browser, or by clicking on a link, the filtering software checks that domain name or Ip address against a previously compiled “control list” that may contain up to hundreds of thousands of URLs.  The three companies deposed in this case have control lists containing between 200,000 and 600,000 URLs.  These lists determine which URLs will be blocked.

Filtering software companies divide their control lists into multiple categories for which they have created unique definitions.  SurfControl uses 40 such categories, N2H2 uses 35 categories (and seven “exception” categories), Websense uses 30 categories, and Secure Computing uses 30 categories.  Filtering software customers choose which categories of URLs they wish to enable.  A user “enables” a category in a filtering program by configuring the program to block all of the Web pages listed in that category.  The following is a list of the categories offered by each of these four filtering programs.  SurfControl’s Cyber Patrol offers the following categories:  Adult/Sexually Explicit; Advertisements; Arts & Entertainment; Chat; Computing & Internet; Criminal Skills; Drugs, Alcohol & Tobacco; Education; Finance & Investment; Food & Drink; Gambling; Games; Glamour & Intimate Apparel; Government & Politics; Hacking; Hate Speech; Health & Medicine; Hobbies & Recreation; Hosting Sites; Job Search & Career Development; Kids’ Sites; Lifestyle & Culture; Motor Vehicles; News; Personals & Dating; Photo Searches; Real Estate; Reference; Religion; Remote Proxies; Sex Education; Search Engines; Shopping; Sports; Streaming Media; Travel; Usenet News; Violence; Weapons; and Web-based Email.