You’ve seen those little transparent advertisements that television networks seem to love putting at the bottom of your favorite TV show, right? You know the ones… they’re usually advertising some other show on the network or announcing when new episodes of some show start. They pop up, do their thing, and disappear.

Google has decided that what works for television just might work for online video. The search company has announced plans to roll out this type of transparent advertising on YouTube, answering a question a lot of us have been asking for months: how is Google going to make back that $1.65 billion it spent on the video portal?

The ads will appear on the bottom of the video player 20 seconds or so into the video. These ads are animated and will take up about 1/5 of the screen. They’re almost completely transparent so as to stay as out of the way as possible. After 10 seconds, they’re gone. Users can close the ads out immediately. If they do click on an ad, the currently playing video will pause, the ad will appear in an overlay window, and then disappear. Once the ad is done (or closed), the video that was originally playing will reappear.

This is really big news. I know what you’re thinking: ads… how are ads big news? Just take a look at Techmeme. Everyone from The New York Times to Search Engine Land to The Wall Street Journal is covering this (and everyone in between). I’d especially recommend checking out Search Engine Land’s post - they have pictures.

So why is this big news? Online video is a massively-expanding market. It seems like someone new jumps into the mix on a daily basis. And while some of these players are making a little money, there isn’t a wildly successful advertising platform out there yet. Some people do pre- and post-roll. Some are trying contextual text and graphic ads. But so far, none of these has really proven to be as successful as - say - search advertising.

As the most popular online video destination all eyes are already one YouTube. When you factor in that this is a Google-related advertising experiment (and we all know that Google is now an advertising company), it’s got “high profile” written all over it. I’m not sure any other video destination could pull off an experiment of this magnitude either.

Will it work? Time will tell. I think it has a decent shot of not irritating viewers. As for actual revenue generation? I’m not as sure. Unless the ads themselves are as good or better than the video you’re watching, what’s the incentive to click? Why would I disrupt a video I’m enjoying to watch an ad… unless it’s just as enjoyable as the video I’m looking at.

So who does the burden of proof fall to here? Advertisers. They’re going to have to come up with some pretty engaging ads to convince people to stop watching the video they came to the site for.