This applet supports both Twitter, and Identi.ca. You can send tweets, direct messages, see your timeline, retweet, and answer direct messages. It will alert you when there are new tweets, and directed messages.
On the first time, you need to choose which network to add, once at a time by right-click -> Add account -> Twitter or Identi.ca. The applet is going to ask your nickname and authorization to connect on the networks.
The network authorization page will be open.
As soon as you authorize it, a PIN number will be shown on the page, copy this number
Paste this number on the next dialog box will be shown.
The plugin is going to inform that you are successfully connected.