Twitternode creates nodes from a specified Twitter feed. It downloads new content from the feed each time cron runs. Nodes created by Twitternode are standard Drupal nodes, and thus can be extended by CCK, included in Views, etc.
Twitternode attempts to play nice with the Twitter API and only requests the most recent status updates. Also, because it keeps the updates as nodes, it effectively functions as a local cache of that Twitter account. Other modules and widgets tend to grab the latest updates straight from Twitter on each page load, which I find incredibly wasteful.