Always have a Plan B, I am backing up all my tweets to my own site evolvingviews.com running #WordPress. Will also use it to write a little more beyond the 280 chars limit. It’s very easy to setup your own site, even for free.
Not that I am worried about Twitter blocking my account. But just realised that I have over 4000 tweets, why should I just leave these on Twitter for them to get more page views and ad revenue? Hosting your own site is cheap, a few bucks a month or even free WordPress hosting can give you much more control with your content. Use Twitter to broadcast it out, but have another copy on your own site for parallel growth.
Just install WordPress somewhere, then add the plugin below by Ozh to import all your tweets. If you have over 3200 tweets, you will need to download the archive from Twitter and run the import again, there are instructions on the setup page. You might also need the Bulk Delete plugin to remove all posts and try a few times. (Remember to import to a new/specific category, so you can delete all and try again to get it right.)