With the first release in 2004, Ubuntu established itself as one of the most user-friendly GNU/Linux distributions available. Since then, each release has reaffirmed this reputation, although recent versions have coasted a little.
However, with the supposedly improved notifications system in the recently-released Jaunty Jackalope (aka 9.0.4), Ubuntu unintentionally raises a new issue in usability -- that is, whether a distribution can or should set the usability agenda by itself?
The fact that Ubuntu should be the distribution where this issue arises seems inevitable. Admittedly, a GNU/Linux user's experience these days is usually determined by changes to the GNOME and KDE desktop rather than the choice of distribution. However, you only have to compare Ubuntu to its parent distribution Debian to see how much Ubuntu has made usability issues their own.
http://www.linuxlinks.com/portal/news/article.php?story=20090428135230344