OK, bloggers and embedders of videos that may contain music for which ASCAP has not issued a license for performance on the interwide webs: You might owe some money. Maybe a shit-ton of money. According to Gawker:
ASCAP sent collection letters to...website owners in the spring; YouTube told recipients to refer the group back to YouTube. But then a judge ruled Google owed ASCAP $1.6 million while a court fight between the two sides over licensing drags on.
So, most people with personal blogs should be fine, but if you, uh, have embedded videos on "a larger venture than simply a personal blog," you might, uh, get a letter from the American Society of Composers, Authors and Publishers at some point. You could already be a winner!
Seriously, though, should everything be free?