This is a great question actually, and one that deserves a blog posting so everyone can read it and benefit.
There are 2 primary ways social media (Twitter, Facebook, blogging, etc…) helps your rankings in Google:
1) A source for generating backlinks. As much as Google, and their search algorithm, has changed over the years, one thing still remains true – who links to you matters!
Getting high quality backlinks from authoritative sources always has been, and probably always will be, the #1 determining factor in search rankings.
Social media platforms such as Twitter and Facebook can influence backlinking because a lot of what’s shared in these places is links.
Look at Twitter for example, the short URL industry has evolved so that people can share links more efficiently without eating up the precious 140 character limit (bit.ly is a great example).
The more people share links to your site on Twitter and Facebook, the exposure you site gets. And exposure leads to more links.
2) Building your brand means everything. Google has, quite frankly, gotten sick and tired of all the spammy SEO strategies that people use to artificially inflate rankings.
This has even cause Eric Schmidt, the CEO of Google, to call the internet “one big cess pool.” Basically, it’s an internet full of garbage, spam, scams, and more!
To weed out the garbage and bring high quality sites to the top, Google is now relying heavily upon factors that show a true brand.
For example, if you have a strong brand, then high quality sites will link back to you – if you have a strong brand, then you’ll get visitors coming back to your site more than once – if you have a strong brand, then other sites will be talking about you.
Social networking sites like Facebook and Twitter provide a great platform for building a strong brand. It’s never been easier to spread information about you and your business, and get other people talking about you.
Sure, it’s not going to happen overnight, but with consistent effort, and producing valuable content that helps your audience, then eventually your business (your brand) will start to get noticed.