It's where people hear about your book.
If you don't believe me, here's the latest piece of evidence:
It's funny how we decide to pick up books sometimes. I was introduced to David Eddings by some fanboy-types I knew while going to college. I think I'm grateful I wasn't running with the Oprah-crowd back then. I don't think I could handle the angst.
Anyway. The Breach by Patrick Lee is a book I wouldn't have even known about if it weren't for John DeNardo over at SF Signal and I might still have passed it up if it wasn't for the occasional tweet to remind people that it might be worth checking out.
So I picked it up over the holidays and I probably read it faster than anything else I picked up in the last year.
Read the rest of the blog post here.
If you are an author and you want to reach your audience, there's no substitute for an effective twitter presence.