Now Google also adds a link that lets you send a thank you note to the person that +1'd page: "Your +1 helped me find this. Thank you!". It's a cute idea and this also helps Google find the recommendations that were really useful, but the links clutter Google's results pages. Maybe Google could show the "thank you" link when you +1 the page.
Another issue is that social annotations aren't necessary when it comes to the top result for a navigational query. Most people that search for [Yahoo] want to visit Yahoo's homepage or use services like Yahoo Mail, Yahoo News, so the annotations for these results are unnecessary. It's probably a better idea to show the annotations less often and only for the results that deserve to be highlighted.
{ via Search Engine Roundtable }