So it's probably been made abundantly clear, via multiple news stories and finding the functionality yourself as Google presents search results via it's Google+ service, that search has expanded to social, titled 'search, plus your world.'
And we also know, as the BBC reports, that Twitter isn't such a fan of this integration by Google, going so far as to say it is a "bad day for the internet." These comments have been made for the public facing reason of Twitter being a source of real-time information, which should be there for the user who wants the most relevant and up-to-date content. The more behind-the-scenes reasoning probably relates to their network not taking any precedence on the search, due to their partnership with Google ending quite a while ago.
Social networking strops aside, points have been made on both sides, and it's why I think Google's expanded social search isn't the best idea they've come up with, for both non-users and users of Google+. It's not going to benefit the people because it contradicts the foundation of such an impactful product as search. It does this in two ways.