The ad-free ride on YouTube has ended. Today Google is launching "overlay" ads that will appear 15 seconds after the clip begins, running for 10 seconds on the lower fifth of the playback image. Viewers will be able close the ads, let them play, or click thru to the advertisers. At the start, the ads will only appear on clips provided by YouTube's media content provider partners. Google is charging advertisers $20 for every 1000 plays. Shouldn't be too long before they recoup the $1.65B cost of buying YouTube. Ten second ads don't seem too intrusive for a great resource like YouTube.