Twitter Lists Aren't About You
If you think the new Twitter Lists feature was designed to help you organize the people you follow, you would be dead wrong. On the surface Twitter Lists help you organize tweets into something sensible, but there's something more in those lists. What Twitter lists really do is provide Twitter with semantic relationships between Twitter accounts, while also establishing the real authority figures on Twitter.
Twitter can already see you are interested in the people you follow. You could also draw the conclusion that Twitter can see you are interested in people who follow you. In a reciprocal follow relationship, there's an implied stronger bond between two tweeters. That reciprocity is devalued by all of the marketing morons intent on building follower numbers. None of who you follow vs. who follows you data gives Twitter the ability to develop semantics around user accounts.
Twitter Lists create those semantics. Each time 2 people appear on a list together, Twitter can begin to group those two people into buckets. The more lists any two people appear on, the more likely they are to be closely linked in some way. So if Robert Scoble and I appear on a list called Tech Bloggers, a list called Tech Influencers, and also appear on a third list called Geeks with Kids, there's obviously some similarity between the two of us.
Lists also establish authority. Just like multiple links from reliable sites translate to greater relevance in search, the more people who put someone on a list, the more likely that person is to be relevant. While you could probably discount everyone who adds Shaq to a Twitter list as being a fanboy, anyone who adds my friend Kevin O'Keefe to a list probably considers him relevant to what they are doing online.
The net result of this should be a Twitter search with more relevant results. In addition to showing the latest tweets on a topic, Twitter search should be able to evaluate that certain people are better able to provide data on Seattle (where I live), or Tech (what I'm passionate about) than others. And if I'm signed in to Twitter, this should be further enhanced by an algorithm that provides results based on how other Twitter accounts relate to mine.
Who this ultimately helps is Twitter partners who get the "fire hose" live stream of data. If Bing and Google can use semantic relationships and list affinity to evaluate the relevance of tweets, there's more benefit for them in aggregating your data. So the question becomes: which lists are you on?