Tweetake is the brainchild of Alfred Armstrong and Nikki Pilkington. Log on to the site using your Twitter username and password and you can backup your followers, friends, favourites, tweets and direct messages, either separately or all at once.
I did the ‘everything’ backup, and in about two minutes was staring at an Excel spreadsheet (the data saves in CSV format) which contained well over 3000 fields, listed in the same order as the categories above. About 2000 were my actual tweets.
(Note: the site claims that having TweetDeck running in the background when doing a backup can cause problems. I had my TweetDeck open the entire time and didn’t have any trouble.)
It’s fairly useful I suppose if you want to immortalise yourself or possibly produce some manner of print-out or book (maybe for a friend who really likes the idea of Twitter but refuses to buy a computer) but it’s not a real backup, simply because if, as the site suggests, Twitter crashes and loses some of your data (as happened in July 2008), you can’t actually restore your account using the backup. You’re still very much at Twitter’s mercy.
So, unless the worst happens and you want to copy and paste all those brilliant tweets back into your stream, Tweetake will probably only suffice if you really want to keep a hardcopy of everything. I’m not exactly sure why you would want to do that, but we all have our reasons.