Just chat with Brad Horowitz (I didn't realise i was sitting just behind him!), about making the Yahoo APIs commercially available. "There's no problem to use our APIs in a commercial environment. You just have to talk to us to work out a deal", says Yahoo's VP of technology development. According to Brad, money does not necessarily have to change hands. He probably means something like revenue sharing. You can find more about Yahoo's APIs for your mashups at their developer corner. At the conference, Yahoo also announced the coming out very soon of their mail API. They were probably waiting for the unlimited storage email announcement.