This is a huge issue cerconerning internet users and people using IM programs such as Xfire due to the fact friends of friends can chat with each other and just text each other, etc.
There was a HOAX SITE recently made concerning Michael Jackson soon after his death. Once you actually enter the site, supposedly you contract a very nasty TROJAN or WORM or MALWARE. You can also randomly recieve an email about Michael Jackson with a link. Other things accompany it as well. More info on this can be found HERE or on GOOGLE
Have I actually seen the link with my own eyes? No. But I know people who have been affected by it and have seen warnings.