"Many Linux projects use Debian Linux as their code base for
developing their distributions. Perhaps as many as 120
distributions are based on Debian and some include SimplyMepis,
sidux, KNOPPIX, Elive, and Parsix. Perhaps the most widely known
and used is Ubuntu. Ubuntu receives negative comments because many
feel its developers don't contribute back upstream.
"One of the reasons derivative projects don't give back is how
difficult and time consuming the process can be. Many just don't
know what to do. So Debian has created a contact point to
facilitate the practice."