You can't talk about marketshare with mobile OSes until you talk scope. There are currently over 4 billion people which use a mobile device. Symbian sits with over 40+% of those users.

Platforms such as Maemo and Android will start eating away at other folks before hitting the majors (Symbian, RIM, Linux).

Android is positioned to take the aged Windows Mobile market, and to be a "best choice" solution for those companies looking to maximize internal development resources, without needing to build the entire OS from scratch. This puts Android in a position to be the cheap, commodized, connected mobile platform - exactly what carriers need in the mid and low-ranges of *all* mobile users to stay relevant.

Maemo will hit a slightly different niche, and depending on how polished Nokia's execution is, it will (within about 3-5yrs time) take place as a major vertical OS for Nokia. It will take over much of Symbian's high-end aspirations for Nokia, but at the same time, stay just enough off-centered that it will not appeal for many of the carriers that want Nokia, but want more control over their devices. Maemo is just as much an innovation engine as it is a developer platform. Watch this space, Apple is going the same route, and RIM is probably considering it too.

Is there a compairson between Maemo and Android, yes, to a degree. However, its the aims of each which are quite different (right now) and how Google is going scattershot with this approach and Nokia is going at it with more of a single-shot sniper rifle. Both will be successful, the key is execution and the services (analytics within these produce data which can be sold/researched/resold, turning people and their relationships into the $$$ that fund the platforms). Google has a considerable lead here, but Nokia isn't as far behind as some would think.