TweepML just launched that makes it easy to create and share groups of Twitter users. It's more than just a grouping service though, TweepML is also an open extensible format. What OPML is to RSS, TweepML is to Twitter.A new service called
Groups are of course one of the core features of social software, but up till now it's been relatively cumbersome to create groups of Twitter users - even in otherwise feature-packed Twitter clients like TweetDeck and Peoplebrowsr. TweepML makes this process real simple.
As an example, here is a group I created for the ReadWriteWeb writing team: http://tweepml.org/ReadWriteWeb/. Simply click on that link, scroll to the bottom of the page, enter your Twitter login details (TweepML states that it doesn't store that data) and click the "Follow" button. Voila, you're following all of the ReadWriteWeb team!
As well as making it easy to create groups, TweepML enables its users to share them too. There are 'follow' counts on the homepage, showing how many people have followed each group.
In addition to the groups service, TweepML is also announcing an Open Standard Extensible format. This is an XML-based format, similar to the RSS grouping format OPML, for applications and services to share lists of Twitter users. An example use is publishers adding a "tweepml.tml" file to their site listing its writers. We will look to do that for ReadWriteWeb, using the above file.