I have been a Twitter enthusiast for a couple of years now. The applications I have most used with Twitter are these:
bit.ly -- the site that shortens URLs. Many of my tweets are for the purpose of flagging up my own blog posts, or linking to other things I've found online; there's an obvious point to a service that will shorten the web addresses of those things to fit within Twitter's 140-character limit. Will bit.ly become redundant now that Twitter has taken to automatically shortening URLs that appear in tweets? Not for me: I like to see how many characters are left while I'm still preparing the tweet; and another thing that bit.ly does, besides shortening URLs, is generate QR codes from them. I'm glad to see that 23things will be getting on to those later.
Twitterfeed -- the site that turns blog posts into tweets. Or rather, that generates tweets including links to new blog posts, together with as many characters from the heading and the top of the post as it can fit in. I have found this invaluable for the Haddon Library blog. I rarely get to see Twitter when I'm at work (in truth, my rule is to avoid Twitter at work unless my email inbox and 'Received' folder are completely empty), and, as I'm the only tweeter in the Haddon Library team, that means that the Haddon Library's Twitter stream won't get updated from the Haddon Library. But now, it doesn't need to be. I can update the blog, and, thanks to Twitterfeed, the blog will do the tweeting for me. For help in teaching the blog to tweet I must thank Niamh.
For my own personal blog, I've gone for the opposite effect. Instead of making the blog update Twitter, I've set up my Twitter account to put my latest tweets on the blog (see right). But that uses a widget I found via Twitter itself, so presumably not as adventurous as some other external applications. Many of those applications require the user to share Twitter login details, and I'm reluctant to do that more widely than I have to. And my tweeting, up to now, has been from the standard Twitter page on the web, or even from a dumb mobile, rather than from more elaborate clients.
Perhaps that's a personal idiosyncrasy. My teenage enthusiasm for distant radio stations was gratified using the most basic equipment -- portable or even pocket-size, medium wave.