NY Times: The Plus in Google is Mostly for Google, 2014
The value of Plus has only increased in the last year, as search advertising, Google’s main source of profits, has slowed. At the same time, advertising based on the kind of information gleaned from what people talk about, do and share online, rather than simply what they search for, has become more important....
The company has also pushed brands to join Plus, offering a powerful incentive in exchange — prime placement on the right-hand side of search results, with photos and promotional posts.
“It is literally promotion that money can’t buy,” Mr. Elliott said. “It is something that Google could make billions off of if they sell that space tomorrow, and they’re giving it away to try to get people onto the social platform.”