Smashfuse is a basic, straightforward search engine which searches various different social media platforms, either individually or in combination. You can see the list in icon form:
If you're unfamiliar with all of the icons they are Facebook, Twitter, Google+, YouTube, Pinterest, Vimeo, Tumblr, Flickr, Instagram and Vine. The results are displayed in a cube like display:
This makes it quick to see what's immediately in front of you, but the disadvantage is that when you start to scroll it can be a little tedious and slow to catch up. If you search 'All' there really is a huge amount of material from Twitter, and that's not surprising, given the amount of data that gets published there every second. I found that I got more useful results by choosing to search platform by platform, rather than try and gulp down everything in one go.
I have no idea what the search functionality is, since there's no help or support options, but it does support phrase searching at the very least, but not Boolean.