You'd think Google would have done this long ago – when they realized how much money they were sinking into YouTube. After all, that very same concept is what makes Google searching so profitable for them. The delay in implementation, according to a YouTube product manager, was apparently technical in nature, and they've had it in mind for some time.
The big question that remains now is, will it be enough? Combined with the numerous other steps Google has taken to make YouTube a revenue generator, such as advertisements in videos and AdWords, I'd certainly hope so. I don't want to see YouTube become a tirade of never-ending ads.