True, I believe that it is a simple reasoning: more people on Google+ leads to the better targeting for a wider audience, so better ads and more revenue. The so

True, I believe that it is a simple reasoning: more people on Google+ leads to the better targeting for a wider audience, so better ads and more revenue. The social interaction is just another channel of information. As you said, why is it so strange? It makes a lot of sense from a marketing point of view (the business strategy dictates so) and an engineering point of view (they already have a commenting system for users).