Because they have published an open API, Twitter has spawned a slewof applications. Here is a list of applications that appear in The Twitter Book by O’Reilly.

Twitter Shrinkers

140it will trim down your post to conform to the 140 character limit.

Bit.ly will shrink a long URL, and will also allow you track the clickthroughs

is.gd shrinks down a URL really tightly, but does not allow tracking

Twi.bz shrinks down a URL, but preserves the underlying domain.

So, let’s see what these services would produce. Let’s say I’m posting a tweet that points to a blog entry at http://www.techfornonprofits.com…. Here is the original URL:

http://www.techfornonprofits.com/blogger/2010/01/sample-grant-policies-and-procedures.html

Bit.ly shrinks this to: http://bit.ly/4DKNhb

is.gd shrinks this to: http://is.gd/72s3T As they say, 72 characters shorter!

Twi.bz shrinks this to: http://techfornonprofits.twi.bz/a Indeed it preserves the domain name.

Searches and Trends

http://search.twitter.com

http://hashtags.org

http://tagal.us

http://whatthetrend.com

http://monitter.com allows you to monitor multiple topics in realtime.

http://tweetmeme.com
monitors links posted in Twitter, and ranks them by popularity in real time.

Clients

http://www.twhirl.org/

http://tweetdeck.com/

Combination of Client + Search + Stats

http://www.twitscoop.com
Still trying to figure this out. Check out the interactive topic cloud.

http://twopular.com/ shows trending topics over various time spans

Organize a Tweetup
http://twtvite.com/