I have a blog and a tumblr, both which have about 300 followers, a deviantart account which has 2900 watchers, and I'm involved in doll forums.
I don't use facebook or twitter, mainly because I just feel they're not for me, but each person needs to find what works best.
A good way to get interest is to be able to talk about or post content that isn't always related to your store. You show a part of yourself that people relate to. I especially like tumblr for this because it's a largely image based blogging platform, so I don't have to have something amazing or witty to say to connect with people. I post pictures of things I like, and reblog other people's pictures. Then I slip in pictures of my own work, so it's not this constant promotion. The way tumblr works is that if you like what someone posts, you can either like it like on FB, or reblog it on to your own blog. If you have something people really like, it can go viral. I've seen quite a few etsy sellers get a lot of attention because of it.
This is my page if you want to see what it looks like (warning, it can be a bit not safe for work sometimes):
http://kawaiimon.tumblr.com/A similar thing is pinterest, which I know a lot of people enjoy, but I haven't used myself because I feel it's too close to tumblr. You "pin" links to images and pages that you like, like a virtual pinboard. In other teams I've been in people have pinned each other's work as a way of helping promote each other. Again, if you like it, you can repin it on to your own page.