One day after Branch launched, Biz Stone and Evan Williams have unveiled the latest project from the Obvious corporation: Medium.com. It's an attempt at creating a new type of online publishing platform, but the ambitions behind the project seem as "grandiose" as they are vague. Medium primarily consists of "collections" of content laid out in a fluid, clean way. Collections can either be private in a way that's more analogous to a blog or allow for contributions from other members in a way that might be more analogous to, say, a Flickr group. Collections can sorted by rating, and the layout changes dynamically in a rather elegant way depending on the size of your browser window. The design of individual articles and photos (with perhaps other types of media on the way) is dictated by templates, and supposedly posting is lightweight and easy — though since it's a closed beta, it's impossible to know exactly what that looks like just yet.
Williams says that Medium is far from complete, but will "evolve rapidly as we experiment and learn from usage." Currently, only a small, handchosen group is able to post on Medium, though anybody can sign up via Twitter to rate posts and browse. In the meantime, there are a few collections you can look at now to get a feel for the reading experience.