Fans of the popular Seesmic Twitter client’s web-based interface have some good news today. A major update to the web interface brings in a brand new contact manager, drag-and-drop full Twitter list management, photo uploads with geotagging, Tweetmeme support and a conversational threading feature that lets you call up back-and-forth exchanges you’ve had on Twitter into a collated conversation pop-up view.

We had a chance to check out the new features and are especially excited about the conversational threads feature. Pictured below, the new option aggregates Twitter conversations into a pop-up chronological view of @replies that transpired during the Twitter exchange between you and user user(s). It’s a great way to pull in a cohesive view of a Twitter conversation, available wherever you see the “in reply to” link beneath an individual tweet. It doesn’t even have to be your own conversation thread; you can enable it to get a clearer picture of conversations among those you follow as well.

The other big new addition is a contact manager, a new feature exclusive to Seesmic (pictured below). At the top left you’ll see toggle buttons between Home, Messages and Contacts. Clicking the Contacts button takes you to the new address book-like tool that collates information about your followers, the people following you, and members of any of your Lists. You can send messages and follow or unfollow individual Twitter users from here, see their bios, and drag and drop them into existing lists (or create new lists).

List management is another new feature in this Seesmic Web update, and the drag and drop functionality is intuitive and easy to use. Inline photo uploading is also now supported, with the status update entry box containing a “Picture” button at the bottom allowing you to include a photo in your tweet from either your local machine or the web. The “Location” button next to the Picture button also allows you to enable the geolocation information to be sent with your update (requires Google Gears to be installed).

In addition to the new functionality, Seesmic Web also got a number of design tweaks and improvements for an easier-to-use interface. Are you a user of Seesmic Web? What do you think of the changes?