Dan Zarrella, the "Social Media Scientist" of HubSpot, just published some very interesting finds about the optimal placement of links in Tweets. His findings suggest that placing the link about 25% of the way through the post (or at the very end) provides the highest click-through-rate (CTR). If you're using TypePad's built in distribution tool then your links will be automatically placed at the end, with your post title filling the body of the Tweet. This seems to be the best approach for the majority of users.
We'd love to hear from you about your own experience. Do you experiment with your Tweet text and link placement? What works best?