By contrast, the Debian community has a reputation of being a more aggressive place -- one that has sometimes been accused of being unfriendly to women in particular and newcomers in general. This atmosphere has improved in the last few years, but can still flare up.
One reason for this atmosphere is that Debian is an institutionalized meritocracy. Although non-developers can write documentation, test bugs or be part of a team, becoming a full Debian Developer is a demanding process, in which candidates must be sponsored by an existing developer, and repeatedly prove their competence and commitment.
That said, among full developers, Debian is a radical democracy, with its own constitution outlining how it is run and how decisions are made. The Debian Leader is elected by the Condorcet method of ballot counting, and has more power to control than to coordinate. Instead, mailing lists are used to discuss problems to the point of exhaustion, and general resolutions about distribution policy may follow.
One reason that Debian discussions have a reputation for unruliness may simply be that much of the governance is done in public by dedicated people.
Ubuntu shares the tendency to meritocracy and transparency that is part of most free software projects. However, although that spirit prevails most of the time in daily interactions, ultimately, major policy decisions are determined by Mark Shuttleworth, Ubuntu's founder and self-described benevolent dictator for life. Those who work closely with Shuttleworth -- most frequently, Canonical employees -- also tend to have a larger say than others in the Ubuntu community. However, this authority tends not to be exercised except for deciding major strategic directions, and, even then, only after monitoring of community discussion.
In the end, the difference between the Debian and Ubuntu communities lies in their core values. Although less important than a few years ago, Debian remains a community-based distribution, dedicated to its own concepts of software freedom and meritocratic democracy, even at the expense of rapid decision making. Ubuntu, however, for all its strong community, is also the key to Canonical's success as a business. If Ubuntu is more hierarchical than Debian, it is still more open than the majority of high-tech companies.
Despite their common origin, Debian and Ubuntu today are significantly different. When you are choosing between them, the decision is not a case of right or wrong, or of superiority or inferiority, but of what matters to you.
On the one hand, since Ubuntu forked, Debian has continued much as it always has. As a distro, it is aimed at all levels of users. It favors free software ideals, de-emphasizing proprietary software and seeing upstream projects such as GNOME as the place where changes should occur, rather than the distribution. Yet, at the same time, its community values prompt Debian to give the maximum freedom of choice in their software.
In order to maintain these imperatives, Debian is perfectly willing to have long periods between releases and outdated official releases, because it is a community effort, in which business values such as timeliness and being current are secondary concerns.
On the other hand, Ubuntu has singled out the new user as its audience. While it has by no means abandoned free software ideals, it is more likely than Debian to countenance proprietary software, either for the convenience of users or to make the distribution more competitive as a product. Meeting its release schedule is at least as important as software quality in Ubuntu, and commercial success is important enough that Ubuntu developers are willing to make changes in the distribution rather than upstream in order to have them as soon as possible. Generally, Ubuntu is a friendlier place than Debian, but also a less democratic one.
For many people, the ideal distribution would probably have aspects of both Debian and Ubuntu. But, since that ideal does not exist, in the end making a choice is a tradeoff. Users must decide which values or tendencies matter most to them, and choose from there, knowing that either choice may not be entirely satisfactory.