In the old days, USENET had EVERYTHING. Probably still does.
One of the sources of constant amazement to me is the seeming ignorance people have about the 'Net. Congress, politicians, the media, seemingly everyone, all labor under the mistake impression that the Internet = The World Wide Web. NOT. The 'web" is only part of what's out there. USENET (newsgroups) still exist, and newsgroups are not "web sites" - in fact, they're not sites at all. Usenet is an anarchous loosely governed comglomeration of news servers around the world, most peering each other, that don't "host" anything but simply store and relay "messages." Anyone with a news feed can get newsgroups, and most ISP's include a newsfeed. With over 80,000 newsgroups, there's something for everyone - music, travel, aviation, model railroads, literary discussion, home improvement, software ("warez"), cars, etc...and yes, porn. There are groups where you can, if you're patient, "find" almost anything, but the members have posted such illegal items in chopped-up formats that deter all but the most dedicated from "stumbling across and viewing" the material.
Then, there's IRC chat ("undernet"). Chat groups that exist for trading purposes, but NOT like email. Then, there are ftp sites, some that are only up for a random hour or so each day. Instant messaging is another. Fact is, there is a LOT of STUFF moving along the spine that ain't "the web."
But don't expect Congress or most parents, for that matter, to understand how all this works.
You can put in all the filters you want and look at your kid's browser history list until you're blue in the face - and never see 1/10th of what that computer might have been used for.
The "WEB" is ONLY THE BEGINNING.
Michael