Twanalyst analyses your Twitter profile and your last 100 tweets (if you've written that many yet) - then makes some sweeping judgements about your personality based on how often you tweet, how many friends and followers you have, the content of your tweets and so on. There are more than 30,000 different possible results the site can give. If you're offended by what it says - don't be: it's just a bit of fun, dude! On a more serious note, the site also analyses the above to make some practical suggestions as to how you can improve your tweeting or increase your follower count. Thanks for trying it out, and enjoy!
The readability figure is based on the Automated Readability Index - this looks at the length of sentences and individual words you use to assess the complexity of the writing. A score between about 6 and 12 represents normal prose: below is simplistic and above is technical or obscure.
The site reads your Twitter profile and your recent tweets - the numbers of friends and followers are particularly important, and the type of tweet you write most often, ie whether you are replying to other people, sharing links, using hashtags, retweeting or just writing something. There are now 15 overall types suggested. These, from most common down to the rarest (figures are approximate) are:
How does the /suggest feature work? It finds other Twitter users who have things in common with you: namely your Twanalyst personality type, how often they tweet, where they are in the world and what they are interested in. The 'close matches' feature means you have clearly stated interests/location in common - the 'loose matches' list (not everyone will have close matches anyway) shows a range of people who at least have a similar tweeting style to you.
If you're a blogger, you might enjoy the Blogalyser (analyses writing style) or LiveJournal personality test.