Neutrality Ubuntu is a self-sustaining non-profit organization. Canonical does offer commercial support, but they do not spent the 10 million that Mark put into the Ubuntu organization. Aspects and features that have a direct commercial advantage for Canonical are kept separate and are not included in the main distribution. What they add to Ubuntu is always opensource and competitors are free and encouraged to pick it up. (and often they do)
Transparency The complete process is open for everybody to participate. Not just packaging, but creating specs, brainstorming, discussions, etc. Everybody can follow and/or participate. If you think something is lacking and you have the skills to fix it, you can maintain that project in sync with everything else. And if it's a big contribution; you will get free plane tickets to the live meetings, etc.
They polish the learning-curve, not the system The focus of Ubuntu is not a system your mother can use, but a system that teaches you how to set it up for your mother. The learning-curve of system administration in Ubuntu is much more throughout than the actual GUI interfaces. This includes documentation, tweaks and intelligent defaults.
Their marketing targets casual users using opensource ideals They are the poster-child of free software. It's not in your face radical extremist propaghanda, but rather subtle honest compassion that they use to market it. Not in geek-speak, but in human language. Take a look at theUbuntu promise at the front page of ubuntu.com .. some friends (that are casual users) explain their love for Ubuntu as "it's just a very sympathetic project". Which is a much more emotional assessment compared to the "we are no longer suppressed by M$ nazi's with their vendor locking and patent trolls"
They build the community first and then the project They chose a mature, almost gay hippy vibe. This keeps the zealots away. And because the adoption rate stays high; the majority of Ubuntu users are always new users. The majority of people on the forums are always users with 1 to 3 years of experience. They are still eager to share their knowledge and haven't become such geeks that they use xmonad or compile their own kernel. Again, this was all intentional.
They are loyal to upstream They don't diverge from upstream too much. The choices of GNOME/KDE/Linus are all respected; they have a strong tendency not to want to change defaults. They also embrace new technology, even when it's not ready yet, but needs the attention and bug reports. They want to be, in Marks' words, "upstreams rock". They filter and triage the thousands of bug reports by ordinary users into actual useful bug reports that are then posted upstream. Some projects (Debian) do complain that Ubuntu is not cooperating enough. Yet i'm quite sure, that drowning those excellent upstream developers with the noise that launchpad gets wouldn't be very productive for anybody.
They don't misuse their position in the Linux ecosystem They intentionally don't make it easy to add binary repositories and they intentionally break binary compatibility with updates. Because given their position a lot of commercial vendors and hardware suppliers would prefer to just support Ubuntu with binary drivers and software; thereby hurting all the other distributions. This keeps the choice to NOT use Ubuntu alive, and that attitude should demand more respect from the rest of the opensource ecosystem than they are currently getting.
They are predictable They want to play the part of gate-keeper for the complete free software ecosystem. One of the ways to do this is too have regular scheduled released. They are already in sync with gnome and chances are high for KDE to also jump into ship with this schedule. More and more are we seeing other vendors (like Red Had and SUSE) pick the same technology and the same releases as Ubuntu does. And rather than acting all 'you stole our thunder and our patches' they are actually welcoming and encouraging the 'competitors' to do this. They are becoming the heart-beat of the free software world.
They compete with Microsoft and Apple, not other linux distro's This tactical choice explains a lot of points above. Why they welcome integration, synchronisation and cooperation with other distrobutions. How to prevent divide and conquer in the linux ecosystem. More linux users is good for everybody. Not everybody stays with Ubuntu, but the 99% of all new linux users of the last 3 years, have started with Ubuntu. That's the key here. And they aren't just users; they have become advocates for free software. Some will start using it professionally. This benefits Red Hat and SUSE just as much.