I hope the person who wrote about rape is permabanned. There's a line, and that's pretty much miles past it.
If you look down from a last post on a page you see Bookmarks and then tags. You can 'tag' a thread basically with keywords of interest to you. Like in Amazon you can tag books. I guess they are then gathered together by the Wiki Gods and search engines can find the material when someone goes looking for that keyword. Or something vaguely along those lines.