Middle button in Firefox acts weird
 

Currently it takes me to random sites. It'll take me to the same site every time for a given page, but it's not a page that's linked to from the given page.
Last page (forum view) took me to howstuffworks.com. Seems completely random. It's taking me to some weird sites I've never seen before...

OK, if I highlight some text it seems to do a Google "I'm feeling lucky" on that text, but when nothing is copied it still takes me to weird sites, and was doing so before I copied text. Just takes me weird places depending on what page I'm on it seems.

Whoa...that's a cool feature. Didn't know about that one. Anyway, I tested it a bit and it seems like it'll take you to whatever is currently stored in the clipboard (is that a proper *nix term?)....so maybe you had copied or highlighted some text prior to clicking, and you ended up with a search for whatever is in memory.

That's what I thought, but it seemed to change at random without me selecting any text.
Anyway, doesn't do it now. I installed some extensions and now my mouse button works properly (makes the circle with the arrows appear for scrolling).
I think it was Tabbrowser Extensions that did it. Or maby the All-in-one mouse gestures. That would make more sense.

same thing happens to me, and it sucks cuz i'm used to use it to scroll in windows - i really hat e it when i accidently click it when I'm reading something LOL

Try installing the All-in-one mouse gestures extension.