Stumbleupon and Social Sharing
If you are a blogger, you absolutely have to create a Stumbleupon account.
I am seeing a lot of traffic from them.
Next, make sure you have some form of social sharing buttons on your blog (like the ones below this post).
Every time you publish a new post, share it on Stubleupon. Of course you should share your post on other platforms (ie. Facebook, Twitter, Digg etc etc). The import thing is that you share each and every new blog post every time and without fail.
I have to say that for me, at least, Stumbleupon, it by far the biggest source of traffic at the moment.