Moblin is based largely on Fedora, and it's still a work in progress, but its main goal is to optimize performance for Atom and Core 2 processors running on smaller machines. The alpha Intel just released alread has an innovative network connection manager and fast optimized boot times, and it's confirmed to work well with Dell's Mini 9, the Acer Aspire One, and the Eee PC 901 (although right now wi-fi on the Eee is iffy).
Performance is all well and good, but what I'm most interested personally is finding the perfect graphical UI for a netbooks' smaller screen. Right now Moblin is using the Xfce desktop, which is pretty bread and butter. Later in the development they'll switch to a more gussied up UI based on Clutter, which Intel owns.
Last week we saw Jolicloud, a fantastic looking netbook OS that has definitely focused on innovating a new UI for the small screen beyond the ol' desktop-and-icons paradigm. That's what we're waiting for. [Mobilin: Download via Ars Technica]