Given the fact that the company relies so heavily on data when making UI decisions, I have a feeling that Google must have some pretty convincing data that would lead them to copy bing both in search results, and now with these iGoogle options...
Or, they're trying to encourage you to be logged in when you search. IIUC, you won't see "your" personalized picture unless you're logged in and cookied.
We have a winner ^
I read a little while ago that Bing's numbers are holding steady (not sure if they are growing now) while other search sites are shrinking (other than Google obviously) -- guessing this has something to do with it