FROM Search Engine Land:
DEAR MISS GOOGLE: When I searched for something using your service, I found a friend had +1′d one of the of listings. What should one do in this case? GENTLE SEARCHER: It’s always polite in these situations to thank your kind friend. In fact, I’ve added a new “Thank” feature allowing you to do exactly this, though Google+.
Yes, a new Google+ feature has been spotted in the wild that further blends organic results with social information. Early today State of Search and charliesaidthat noticed a thank you link on an organic listing next to the Google+ users who +1′d a result.