Though Twitter officially launched Lists only a week ago, third-party developers are already hard at work implementing the new feature into their applications. Seesmic, a desktop client that supports both Facebook and multiple Twitter accounts, was the first, adding support earlier this week.

Thursday night, Web-based Twitter client Brizzly took second place by announcing that Lists would work with Groups without a hitch. Groups, which, like Lists, allows one to sort other users into categories of any size or specification, is a feature that has been available on Brizzly since the summer.

Brizzly says any Lists a user creates on Twitter will be accessible through Brizzly for navigating through and editing. Additionally, any groups users have created on Brizzly will automatically be transferred to Twitter as private lists, in case anyone had any unfriendly lists they didn't want to share. Brizzly co-founder Jason Shellen says the whole process should be done by Friday night.

If any of this makes you really want to try out this promising third-party client, you'll have to wait. Brizzly is still in closed beta.

Twitter has seriously picked up the pace in terms of releasing new features, having announced four pretty major changes in the past week. Last Friday, Lists was officially rolled out. Earlier this week, it was revealed that the site has been completely translated into Spanish, opening up the site's doors to a massive audience of non-English speakers. Finally, on Thursday, besides announcing the rollout of a Retweet function, Twitter divulged its decision to make Trends more useful by reducing the noise.

For a startup typically criticized for lagging behind Facebook, in terms of its ability to keep its site new with fresh updates, these are some nice changes taking place.