Go ahead and try a Google search for Linux in the news feeds. In fact, try looking up Linux in any news search engine and see what you come up with.
Notice a pattern yet? For some reason that seems to escape most people, Ubuntu "owns" the Linux headlines with very few exceptions. Obviously Chrome OS and Android are in the top news headlines as well, however generally it's Ubuntu that shows up as most popular in open source news these days.
This trend is even more severe among blogs and forum sites. Clearly the Ubuntu way of offering Linux to the masses has caught on to such a degree that it's amazing when new users even realize other distributions exist.
At the risk of sounding like Im bashing on Ubuntu here, I've seen numerous incidents where poor experiences with the distribution have colored opinions of other Linux distributions without any cause. This trend reflects something that I've been concerned about for sometime now: people perceiving Ubuntu as "the" Linux desktop operating system.
Not enough Ubuntu users appear to realize that not every distribution of Linux out there is doing things the "Ubuntu way" with regard to buggy releases and a need to look like OS X, among other issues. Many other Linux distributions out there have varying release schedules and some Linux distributions even wait until their releases are stable before releasing them. Clearly a bold move, as much of Ubuntu's success might be attributed to the "release no matter what mentality" we see these days.
Newbie friendly non-Ubuntu distributions
Need some of the niceties of a new user friendly distribution but would rather avoid Ubuntu's way of doing things? Nothing to fear, alternative distributions are indeed available.
I hold these two examples up for newer Linux hobbyists simply because those who are already comfortable with the non-Ubuntu Linux desktop are likely already using Fedora, OpenSuSE or something Debian based. It's a moot issue for those folks.
New Linux users however, will find that using either Simply Mepis or PCLinuxOS translates into a simple, yet stable alternative that will not leave you shaking your fists at the screen because of an avoidable bug ruining your day.
Both distributions have strong communities while still maintaining a stable, predictable experience followed by a brain-dead simple installation process. Plus, Simply Mepis has utilities that Ubuntu hasn't matched yet. They are Mepis exclusive to the best of my knowledge.
Competing for an audience
Remember back when people used to claim that we lived within a Windows world? Well for many Linux enthusiasts, it feels like we live within an Ubuntu world. At least from the media's perspective.
Now I have a number of theories as to why this might be happening. The first thought would have to be the strong reception from OEMs like Dell, among others, offering Ubuntu. (However, this trend seems to be slowing on Dells part its only showing a single computer with Ubuntu on it at the moment.) However others, such as System76 and Zareason, have made sure that Ubuntu Linux is featured and well supported for their customers.
In addition to that, there are the local Ubuntu teams aka "LoCo Teams" which promote and introduce Ubuntu to potential converts when the opportunity arises. Teams are generally broken up by State/Region, to make membership more manageable.
Ubuntu also has a strong leadership within the community with active participant(s) who work for the supporting company, Canonical. The main person who comes to mind would be the always approachable, Jono Bacon. Despite the fact that I do not always see eye to eye with his views on the subject of Ubuntu, he's a stand up guy in my opinion. And as a result, I think Ubuntu is able to put on a great public face through Jono's outreach efforts.
Sadly other distributions, despite boasting some great communities, lack the kind of community focus that seems to translate well from the virtual world into the real one. PCLinuxOS is pretty close with their PDF-based magazine publication, yet Ubuntu still seems to maintain the larger reach.