Even Wikipedia isn't spared HP wank.

[WARNING: The following contains spoilers rampant, including very detailed (possibly overly so) chapter-by-chapter summary of the book.]

In the Harry Potter and the Half-Blood Prince article, a quiet battle is waged against trolls, as evidenced by the edit history, with troll edits ranging from ridiculously massive to minute and random.

Examples of troll-edits:
Is being excessive a key point of trollery, or something?
Simple and effective. ditto. Further ditto. Son of ditto. ...Really, there's a lot of this sort of thing.
Kind of like those "replace random noun in quote with 'underpants'" games, I guess.

Overall, most of the wankery occurs in some of the various edits, including this paragraph, added by one of the unnamed users to the bottom of the article, since cleared out.

"That Ginny. Is that how you spell it? I almost spelt it with a 'j'. I'm tired, but I need to get this off my head. Ginny is a no-good slut. She is 15 years old and has had what, four boyfriends? Here are them all: Michael Corner (dumped him, said he was a loser) Dean Thomas (they had an argument or something...probably didn't want her looking at other boys, but she didn't listen) And lastly, famous Harry Potter. Okay, that was only three. But I may be wrong. Probably more somewhere. Those are the ones we KNOW about. If I were Ron, I'd say "get away from my sister" and punch them all in the face. Yeah...not like that sissy Rupert Grint. He just doesn't know anything. That's it. That's all I have to say."

And ad infinitum.