Google has been preaching for years about relevancy and unbiased search results. Even testifying in DC - http://searchengineland.com/mr-cutts-goes-to-washington-6123... - Google’s results are determined by an algorithm and not tweaked to get particular sites ranking well. - Yet they now have tweaked their results in order to place their Google+ brand above results that are much more relevant than theirs.
Some might argue, "hey, it is Google's website - they can do what they want." I used to think like this too, but the reality is that this behavior is bad for consumers and bad for businesses. Especially smaller businesses. This isn't just about Facebook and Twitter... there are hundreds of smaller niche content players that will be pushed aside by this. And as Google has to grow to keep shareholders happy, they will have to move into more and more content. If this still seems like a stretch see the example below.
What if there were only 2 companies that owned land in San Francisco and New York? One of them was named Google and they owned 70% of San Francisco and 90% of New York. In the beginning Google allowed anyone to rent their land for retail stores. So you had all different kind of companies providing different kinds of products in their stores. Hundreds of different businesses. Then all of the sudden Google decided to take over those retail locations and sell their own goods. They also sold other company's goods, but they were way back in the store. Hidden away. So if you were walking down the street in New York, 90% of the time a store would be owned by Google and 90% of the time you would only see marginal Google products. Now would that be good for business? Who would go into business? It would be so hard to compete. Would that be good for the consumer?
I believe in free enterprise, but only to a certain extent. There is a reason why antitrust laws exist. If they didn't, companies like Google never would have existed. We would all be working for Rockefeller.