Deleting stuff. Just like with creating unpersons, you can't completely obliterate information. Somebody somewhere has a html copy of some blog you thought you deleted in 2000 just because your description of GAZ 21 Volga cars gives him a weird erection. I've seen it time and again where the information on a website was scraped from another, closed, website which may itself have come from another dead page. Now that you can do screenshots instead of printing it off and then typing it up, the image of whatever catches the collector's fancy is there in his/her hard drive. The way we deal with much information on the web is now like a mosaic, and what was on certain missing pieces can be inferred by references to the missing bits on the surviving components. Jimmy Wales has tried this a lot on his Wikipedia talk-page, burying the times he's stuck his leg into his mouth, but the sheer act of repeated deletion means people will be there taking "before" and "after" screenshots just for laughs.
Wiki-communism. There is a lot of back-and-forth about how Wikipedia is the second coming of Communism because it's a collective organization, with a hierarchy, and lots of rules, and a "beloved"leader-figure....and I have to laugh, because those terms could also describe the American Continental and Militia forces during the American Revolutionary War (or American War of Independence if you are British.) Like the Wikipedists, the soldiers and sailors weren't paid either. Jimbo Wales is not a Marxist; from everything I've read, he is a hard-core fan of Ayn Rand. He wanted ads on Wikipedia and that created the friction between Wales and Larry Sanger (the only guy with a Ph.D [as far as I know] at Bomis, Wales' original company.) In truth, if Wales could charge for different levels of information at Wikipedia, he probably would.....which is why he has tried to capitalize on his leadership/creatorship of Wikipedia in as many ads as possible.
(You knew the reference above had to appear.)