This is in response to a question left by a visitor to my blog.
I have a link back to this blog from my Twitter profile but apparently not many followers click on that (according to my statistics). However, there is some traffic when ever I link a blog post to a Tweet.
I am also using Twitterfeed.com to tweet posts on my ah ok lah blog automatically. I did notice some traffic to the blog from the tweets but nothing spectacular.
So, my answer the question whether twitter actually increases traffic to your blog has to a "probably!" However, you would need to be really famous with thousands of followers to see a noticeable increase in traffic.