Libraries are using so much social media and Twitter is a great tool for fast, short & direct snippets of information. Twitter has millions of users (tweeters!) so it is an excellent tool for all Libraries to connect with its clients. Libraries can use Twitter to advertise inhouse events like storytime or guest speakers, to notify people when the library is closed/open (public holidays), or when new services or books are available.
Twitter is also used for conversation or accessing information from clients or libraries with the use of retweeting and sharing of links, And of course, libraries following other libraries is a great device for new and constant exchange of information.
Check out these library Twitter feeds;
State Library of Victoria @Library_Vic
University of Melbourne @unimelb
Yarra Plenty Library @YarraPlentyLib
For library professional following other professionals worldwide is an active way to gain useful updates within the information industry.