Hey! It's not just me:

Florida State (great Superbowl BTW - nailbiting down to the last seconds!) has a useful article I'm reading now at:http://lis5313.ci.fsu.edu/wiki/index.php/Twittering_Libraries

And this is a quote:

"Yet Another Thing to Update. Remembering to do updates is a difficulty noted by some, especially when the librarian has many other duties to tend to while at work. Many of the libraries using Twitter also have blogs, Facebook/MySpace pages, and the website to continually update, thus making Twitter yet an additional responsibility to an already full workday."