Google might come up with something using AdSense. A lot of websites and blogs use AdSense, I might be interested in supplying images for a cut of the money they make.
I'm really surprised that there hasn't been more innovation in the microstock market. All the sites seem to follow what istock and shutterstock came up with years ago and none of them have managed to become more successful. I'm sure there's lots of ways for us to license our images that are better than the options we have at the moment. There have been a few innovative sites but they haven't been able to make an impression. I'm still hoping there are others with better chances.
Problem is adsense doesn't make that much money for advertisers. The ones that are doing well with it have big sites with often automatically generated content that targets specific keywords. For advertisers the adsense program offers far less transparency than any of the microstocks.