For those interested, this small list of Twitter resources accompanied a great article in the March-April 2011 issue of Writers' Journal magazine by Julie Bloss Kelsey entitled, "Eight Ways That Twitter Can Jump-Start Your Writing Career".
Twapper Keeper: http://www.twapperkeeper.com/ (an archival site of tweets based on hash tags)
Twitter Help Center: http://support.twitter.com/ (Twitter's help section - includes a "Twitter basics area)
What the Hashtag?!: http://www.wthashtag.com/ (an encyclopedia of hash tags used on Twitter)
Writerly Chats: http://www.twitter.com/mamajoules/writerlychats (a list of writing themed chats with Twitter accounts)