Companies are high on social media for a number of reasons, but perhaps chief among them should be that social platforms provide the opportunity to create focus groups at a scale never before possible. Millions of people talk about all sorts of things online, and with the right systems and algorithms in place, it's possible to decipher how they actually feel about the topics they're discussing.
Here's an interesting post from GigaOM about how social media has changed polling practices (for the better? You can decide). Give it a quick read through if you're interested.