With plenty of cash in the bank and a growing talent horde, Twitter looks to be taking the next step forward - which is finally getting around to introducing features that have long been core differentiators brought to the table by third party clients. Following the recent addition of trending topic definitions (following Brizzly's lead), Twitter now has announced it will soon debut lists, which is already being tested to a "small subset of users". For most of us, the term "lists" has heretofore been known as groups, made famous by TweetDeck.
Most interesting about Twitter's move is that these lists are going to be "public by default" even though you have the option to make them private. In fact, these lists are going to be linked from your profile, just like your messages and your favorites are today - letting other Twitter users subscribe to your lists, a big move forward for recommendation-based discovery, along the lines of "Follow Friday", but official.