Dear Friend
This is my opinion as i earlier has given on same topic and Kamal mam already provided you all important links:
Following can be the users' advantages of Twitter.
.Instant messaging between users and library staff.
.Up-to-date and innovative information.
.Quick communication.
.Multimedia data can be provide to user and can get feedback.
.CAS can be provide in effective way.
•User feedback is very useful for library.