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.
1. There's supposed to be the open standard around opening up your web browser and searching for content: an open standard which many people don't feel comfortable with (privacy issues) and hence, don't make their social profiles public.
2. 'Search, plus your world' connotates that people use Google products, which many do not beyond search and Youtube. If search is supposed to be an open plain for the internet, closing it to specifically your set of products is trying to monopolise a market which isn't really what the participatory nature of 'web 2.0' is about.
I enjoy Google and the variety of products I use around it (working on my Gmail filters in a trance-like state); but social search is not something we need or want, because it's not actually fitting into the 'open' definition of a search, and with the single networked community of basis from where it receives these results, it's not actually that social either.