In case you didn't think you needed to be on Google+ since your social media presence on other platforms was "good enough", think again. As of this week Google is rolling out the "Search Plus Your World" feature, basically combining it's data from Google+ in the search results, both providing a more personalized result but also acting as a gateway to Google+.
As you can see on the screenshot below, the search results are now split vertically in two parts: the regular search results (but personalized with information on whether you or your friends shared a link) on the left and on the right related results from Google+. If you search for "music" you get Britney Spears's G+ profile.
Search Engine Land has more examples of these changes
Now, Google says http://bit.ly/x5oIXJ they are not really favoring Google+ and they would want to add Facebook and Twitter on the right-part-of-the-screen results, if they just could make a deal with them. Of course until then, the situation is simple: If you're on Google+ and your competition isn't, you have a possible advantage (you also need to appear on Google's suggestions for your desired keywords). The fact is that Britney Spears didn't appear on the first page of search results for "music" yesterday, now she does.
So how do you get on the action? Google has a guide page http://bit.ly/y0GhHP but it's not really clear. Basically they are saying "get on Google+ and start posting useful content". Good luck then! :)
Google now has it's own internet :)