Recently I have started seeing Google+ profile pictures next to links in Google search results pages. At first I thought it was something to do with people sharing links with Google+ Circles they have added me to, or a special service Google was offering for high ranking websites. Then I noticed that I was seeing avatars even when I wasn't logged in to Google. It turns out that it is a new feature being rolled out by Google and is powered by simple links to and from websites and Google+ profiles.
Google do have a similar feature that shows small avatars of people you follow on Twitter and other networks next to links they have shared that are in your search results. These are effectively recommendations from your social media circle. The use of, much larger, Google+ profile pictures is quite a different thing though. It is not linked to who you follow, or who has shared a link. It is enabled by webmasters adding links to their sites and then Google use their algorithms to work out whether they should show the pictures or not.
The screenshot below shows a Twitter avatar and a Google+ profile pic in a Google search results page:

This is potentially a very powerful tool for bloggers. The eye catching effect of a profile picture next to a link cannot be underestimated. Users will be drawn to these links and will pass over search results that may be higher in the list. Personally, I think this feature alone may force my hand into having to proactively use Google+ when I don't really 'get' the service.
Surely there will come a point of diminishing returns. When this catches on and every blogger and website has their Google+ profile picture next to every link on a search results page we will be back to square one. All the avatars will cancel each other out. Currently, there is only a small, select group of writers whose profiles are used. Maybe Google realise the danger of swamping search results pages and will be quite restrictive in which profiles they show. If this is the case, then being 'in' with Google, or their algorithms, will be a very, very useful thing.