For me, 20% is pretty mainstream, it's almost a quarter of the market, I think that's very impressive considering what they're up against!

Regards me pushing Debian and dissing everything else, you're taking things too literally.  Yeah, I do push Debian in contrast to any commercial OS, but I don't push Debian as being the only alternative to a commercial OS.  I've tried all sorts of distros.  Trisquel is another one I would have no problem using (if only I could).  I can't use Trisquel though, because the hardware on my main box isn't supported due to the lack of open drivers for it.

If I were to use it solely as a web machine, no problem, but I aim to move completely to the new OS, so the drivers have to be good otherwise the graphics performance stinks.  What's good about Debian is it supports a massive amount of platforms and a massive amount of drivers, so much so, there's even a dedicated version of Debian for the Raspberry Pi (Raspbian) - which is the official OS of that device.

For the price of a few Blu-rays, a complete noob can pick up a brand new Raspberry Pi and a ready installed Debian OS.  People can play with GNU/Linux easier then it's ever been possible to do, and all on a dedicated device seperate from their man box.  This is why I push such things, it's not just that it's default OS is Rapbian (Debian), it's that it takes away the scare factor a lot of people have about "Using Linux".