Some may wonder about the point of Twitter, why would people sign up for a service to post 140 character messages. Sure it can be useful for quick information, I've seen it used well in this way for a variety of topics.
What I use Twitter for is community, connecting with those similar to me. It may sound weird to look at Twitter that way. But there is more to the service than the posting of those 140 character messages aka "Tweets".
Hashtags are one way to connect with like minded people. Unlike tags in a blog which organize your own posts Twitter hashtags are hyperlinks to a search for any tweets on twitter using that tag. (As an aside for those unfamiliar with Twitter a hashtag is typed into a tweet by using the # key followed by the word(s) one wishes to use). As a writer, my two favorite hashtags are #amwriting and #storystarters. When I tweet about my writing I use the #amwriting tag in those tweets. #storystarters are for posting well story starters for other writers to use.
With the hashtags I've found other writers on twitter, and I've added followed them. Now their tweets show up in my home feed enabling me to reply to tweets, re-tweet helpful tweets, and simply to have a feel for how others are doing with their writing. I have also posted a few story starters with plans to post more.
Me on Twitter