I came across TweetLens on bmann's blog (Boris Mann). TweetLens is a rich web based Twitter interface that is in alpha preview release built by Vancouver's Ben Wong @mostlygeek. According to Ben, some of the cool things that make Tweetlens awesome are:
Keyboard based navigation
Background status updates
Mark as Read
Hide Read Tweets
One key retweeting and replying
And Boris seems to like those features as well. For him, he says TweetLens acts almost as a Google Reader of Twitter clients.
I think you could call TweetLens the Google Reader of Twitter clients. It has keyboard shortcuts for reading through and acting on posts. Like Google Reader, I can hit spacebar and "close" individual posts, visually indicating that I have actually read something. Like I said, I find this super useful when I'm taking the time to actually sit and "catch up" on reading through posts.
Interesting. Ben is working on fixing bugs as we speak. You can follow @tweetlens for updates or give alpha a try.