How safe are links to videos?

Guys post various links to car videos, plane videos, goofy videos, etc, all the time. But how safe are these links? I'm not extremely savvy on all this virus stuff, but seems to me that a goofy video that thousands of people would like to see would be an excellent place to plant a virus. Is there any history of these video links having any problems? We've all heard about the e-mails with a title like HA HA, A FUNNY STORY and the associated viruses that reek havoc. A funny video link would probably be just as disasterous, especially with a time delayed activation. Load a goofy video, tell the world about it, everybody looks at it, then WHAM, 7 days later the time clock activates the virus and crash goes your hard drive. Can this happen?

 

But that wouldn't cure a "time delayed" virus. Ten thousand people could click on it and watch the video and think it was fine, then after the programmed delay period, the virus could activate and shaft 10,000 people.