N2H2 offers the following categories:  Adults Only; Alcohol; Auction; Chat; Drugs; Electronic Commerce; Employment Search; Free Mail; Free Pages; Gambling; Games; Hate/Discrimination; Illegal; Jokes; Lingerie; Message/Bulletin Boards; Murder/Suicide; News; Nudity; Personal Information; Personals; Pornography; Profanity; Recreation/Entertainment; School Cheating Information; Search Engines; Search Terms; Sex; Sports; Stocks; Swimsuits; Tasteless/Gross; Tobacco; Violence; and Weapons.  The “Nudity” category purports to block only “non-pornographic” images.  The “Sex” category is intended to block only those depictions of sexual activity that are not intended to arouse.  The “Tasteless/Gross” category includes contents such as “tasteless humor” and “graphic medical or accident scene photos.”  Additionally, N2H2 offers seven “exception categories.”  These exception categories include Education, Filtered Search Engine, For Kids, History, Medical, Moderated, and Text/Spoken Only.  When an exception category is enabled, access to any Web site or page via a URL associated with both a category and an exception, for example, both “Sex” and “Education,” will be allowed, even if the customer has enabled the product to otherwise block the category “Sex.”  As of November 15, 2001, of those Web sites categorized by N2H2 as “Sex,” 3.6% were also categorized as “Education,” 2.9% as “Medical,” and 1.6% as “History.”

Websense offers the following categories:  Abortion Advocacy; Advocacy Groups; Adult Material; Business & Economy; Drugs; Education; Entertainment; Gambling; Games; Government; Health; Illegal/Questionable; Information Technology; Internet Communication; Job Search; Militancy/Extremist; News & Media; Productivity Management; Bandwidth Management; Racism/Hate; Religion; Shopping; Society & Lifestyle; Special Events; Sports; Tasteless; Travel; Vehicles; Violence; and Weapons.  The “Adult” category includes “full or partial nudity of individuals,” as well as sites offering “light adult humor and literature” and “[s]exually explicit language.”  The “Sexuality/Pornography” category includes, inter alia, “hard-core adult humor and literature” and “[s]exually explicit language.”  The “Tasteless” category includes “hard-to-stomach sites, including offensive, worthless or useless sites, grotesque or lurid depictions of bodily harm.”  The “Hacking” category blocks “sites providing information on or promoting illegal or questionable access to or use of communications equipment and/or software.”  SmartFilter offers the following categories:  Anonymizers/Translators; Art & Culture; Chat; Criminal Skills; Cults/Occult; Dating; Drugs; Entertainment; Extreme/Obscene/Violence; Gambling; Games; General News; Hate Speech; Humor; Investing; Job Search; Lifestyle; Mature; MP3 Sites; Nudity; On-line Sales; Personal Pages; Politics, Opinion & Religion; Portal Sites; Self-Help/Health; Sex; Sports; Travel; Usenet News; and Webmail.  Most importantly, no category definition used by filtering software