Google introduced Google+ in June 2011, but it has struggled to take off. While it has over 60 million registered users, Facebook has more than 800 million active users, and Twitter has 100 million.
In January, Google announced it would include search “plus your world” at the top of its search results, linking in information from connections’ accounts on Google+ but not from other social networking services such as Facebook, which is much more popular.
"You should also be able to find your own stuff on the web, the people you know and things they've shared with you, as well as the people you don't know but might want to... all from one search box," Amit Singhal wrote of the new integration in a Google blog post.
Bloomberg reported: "The changes sparked a backlash from bloggers, privacy groups and competitors who said the inclusion of Google+ results unfairly promotes the company’s products over other information on the Web."
The look at Google+ is an expansion of an existing probe into whether Google gives unfair advantage to its own services in its search results and overcharges competitors to advertise. The search engine, by far the most popular in the United States, has faced legal hurdles before, such as its recent attempt to digitize large numbers of out of print books, the New York Times reported.