And my blog got 36 visitors to that post.
I know, 36 visitors is not a huge amount, but if you write good, useful, informative posts every day and send out a link to each post twice a day on your social network - once in the morning, once at night, because people check in at different times of the day - and let's say you average 36 visits A DAY...in one month, that would be...let's see, ran out of fingers, taking off my shoes...
More visitors than you started with! And assuming that your site is good and has regularly updated information, some of those visitors should come back regularly on their own.
I believe that when you send the same post out more than once, the etiquette is to start out by saying "retweet".
CORRECTION - APPARENTLY THAT IS USED WHEN YOU ARE POSTING SOMEONE ELSE"S TWITTER.
Final note: Willie Crawford is ALL OVER Twitter, and he is one of the most focused IMers I've seen. I don't think that man sneezes without figuring out a way to monetize it.