First promised earlier this year, Twitter has begun testing the ability for users to download their entire Twitter history – up from the previous limit of 3200 tweets imposed by the Twitter API. The option is currently only available to a small number of users (as confirmed by TheNextWeb), although it’s likely that the feature will roll out to all users in the near future.
To download your history archive, just to into Twitter settings, and scroll down to “Your Twitter Archive” to download all of your tweets. Twitter will send you an email once your archive is ready to download. It will come in the form of a zipper HTML file showing tweets in a calendar-like format.