This is an old listing.
Please download LATEST version here - https://addons.mozilla.org/en-US/firefox/addon/twitzer-twitter-more/
If you want to post more than the 140 character limit at Twitter, install this extension. Now type away as much as you want and before posting just click on "Twitzer text". The extension will automatically save the full text at shortText.com, create a URL and replace the typed text with the summary and URL.
People who follow you can get the full text of the created links on Twitter site itself by clicking on 'De-Twitzer text'.