The new Seesmic Desktop, which will be distributed by e-mail early this week to users registered at http://seesmic.com/team.html, and soon after, be made available through auto-update, automatically discovers lists on Twitter that you have subscribed to, and displays them as options in your sidebar, between Facebook pages and saved searches.
The New Seesmic Desktop (Click to Enlarge)
Those user lists that you are following are displayed with the username and then the name of the list. Those from other Twitter users are shown with a gray Twitter logo, while those you have made are in blue. But whether they are yours or not, they still display the same, in the familiar column format seen on Seesmic Desktop and Web, as well as TweetDeck. On my 15-inch MacBook Pro, I could comfortably fit three lists, while those of you with more impressive displays can no doubt fit many more.
The Twitter Lists feature works just as it does on Twitter Web, letting you add any Twitter user to any list you have. Also announced in today's news was that Seesmic Desktop has surpassed three million individual downloads. You can also expect that Seesmic Web, one favorite of mine, will support the lists feature very soon.