I noticed Google was testing 3 Google Base listings for some queries in the right side sponsored listing. Looks like Google is testing the use of Product/Image listings. I'm sure this is only being tested on a small number of users. I've only been able to replicate it for one gmail account. Anyone else seeing this? Thoughts?
I haven't seen this myself, but we also have another report about some test in Adsense areas - namely Google advertising itself with clickthroughs that go to certain search results. So I'm not surprised that Google Products searches might get tested sometimes.
It's interesting to note that both experiments would not directly increase revenue for Google, but would be more for the end user's convenience.
You are correct that these experiments are not generating revenue, but my guess is that G would start to charge for the product ads if they find the end user prefers it through testing. This is possibly why Adwords has a beta feature to link your Google Base and Google Adwords accounts.
I have asked to accepted into the program, but am still waiting to hear back.