I would second
Alhazred De Sane's response there. I am using Twitter for the past couple of months and my feelings are that if you send good quality messages over time and build followers that it will
eventually drive traffic to your site.
However interaction is important as well as the purpose of the Twitter isn't to say <Here is my great site go visit http://bolggyboy....> as people will get fed up pretty fast and unfollow you (at least I do anyway!!).
Bottom line it is a 2 way street. I (again personally) think you need to have over a 1000 followers to get any degree of traffic generated as it is when a good message gets retweeted that you have the exponential affect of driving traffic and possibly more followers.
Bottom line: It takes time and effort to build followers ignore any ot the viral methods they suck like smelly socks.
Oh and follow me on @kdaly100 for incisive, clever messages !!! LOL