Numbers say that Ubuntu is the fastest growing Linux distribution. Ubuntu has hit the sweet spot of usability for the common man with functionality and freedom of Linux. But nothing better than another possible competitor adopting a part of you can indicate your popularity.
Nexenta is an OS that combines the OpenSolaris kernel with the good old GNU applications with some parts borrowed from Ubuntu. Nexenta borrows elements like Synaptic for package management, some of the system and user settings modules, and the sudo philosophy. This indicates that the Nexenta team is using Ubuntu as a guide to build in usability for the average Joe.
There are other OpenSolaris distributions, but Nexenta is getting proactive to borrow an existing user base in the Linux world. Nexenta will not end up on many desktops today, but is surely worth trying, and will be very interesting to watch. Perhaps Sun can contribute to it.
