Always be cautious when clicking on links from anyone, even if the request comes from a friend on your mailing list. Clicking on the link without verifying it is a legitimate link can do damage, it can cause on line accounts to get hacked and possible irreversible damage to your computer.
Be on the look out for links containing the words "youtu.be". It is designed to look like a shortened youtube link at a quick glance but it could be a link to download a virus mostly like a trojan virus. An example of what a link would look like : http://youtu.be/74343yDG2
Exerts from other reports on the web:
I clicked on the video in reference to a karaoke machine that was for sale. I was able to watch it, but afterwards my computer froze and the next thing I saw was my anti-virus program alerting me of a virus threat:
________vload.class - a variant of Java/TrojanDownloader.Agent.
I would flag the video, but I don't want to expose my system to this risk again."
If you receive a message through email, facebook, forum, or any form of a social site. Don't click on it. If you get or read a message where the link is masked by linked text scroll or mouse over the linked text and the http: source will show.
Also, be on the look out for people claiming the links are fine, especially if you do not know the person, they most likely are a hacker trying to goad people to into thinking their virus ridden link is safe and get very combatant when confronted they flinging insults, will try and get the forum post outing them removed, or they will re-post using a different shortened link.
Just remember it is your computers security and any information stored on it at risk. Unless you are absolutely sure of the source don't click on the link.
UPDATE: PLEASE NOTE THE VIRUS LINKS WITH YOUTU.BE IN THE ADDRESS LINE ARE DESIGNED TO LOOK LIKE LEGIT LINKS WHICH ARE USED BY YOUTUBE. YES, YOUTUBE DOES USE YOUTU.BE IN THEIR LINKS BUT BE AWARE THERE ARE VIRUS LINKS OUT THERE THAT ALSO USE YOUTU.BE IN THE LINK, SO IT APPEARS TO BE LEGIT. EVEN THOUGH THIS IS OBVIOUSLY STATED IN THE ORIGINAL BLOG POST PEOPLE ARE STILL TRYING TO CLAIM I AM SAYING ALL YOUTU.BE LINKS ARE VIRUSES. PEOPLE, PLEASE BE SURE TO COMPREHEND WHAT YOU READ OR I WILL START POSTING YOUR INACCURATE COMMENTS WHICH WILL SHOW HOW WELL YOU DON'T UNDERSTAND WHAT YOU READ AND I WILL NOT BE NICE WITH MY REPLY. I WILL MAKE YOU LOOK LIKE THE ASS YOU ARE!