I went to this page on neohapsis about the latest Linux kernel bug. I kept this URL opened in a tab and I noticed that my CPU was at full load... Weird. Then after looking around for a while I notice "Applet DistCrack.class started", WTF? I promptly banned it with AdBlock+.
Edit: I just noticed that they mention their "research on distributed computing" on the page. This is a bit harsh to me : suck up CPU first and opt out later?