Edit: I didn't quite read the above correctly, I guess I'm actually agreeing here... But anyway, yeah, the difference between other phones and the N900 is that the N900 is running an actual Linux distribution.

Closed-source software, like Windows 3.1, survives only as long as its corporate owner decides to let it live. Windows 3.1 can still run, but can never again be maintained, modified, or improved. All closed-source software faces this bleak future. Whenever you purchase such a piece of software, you should expect that it will be dead someday, and probably someday soon.

Linux is different. The CSSU is a great example -- Nokia may have moved on, but Maemo continues to be improved. Moreover, Linux software continues to be improved, and most of that software can run on the N900, and will continue to for a long, long time to come.

I've been using Linux for something like twenty years now. I'm able to use software on my N900 today that I was using on Sun workstations back in college. I'll probably continue to use the same software on my portable pop-up holographic 3D terminal in the year 2030.

Open-source software never dies.