Big news today for those following mobile RIAs closely. Nokia is buying the remaining 52% of Symbian that it doesn't own and making the mobile platform open source. As Steve O'Hear said, the move is "bold to say the least". At a time when everyone is trying to make a play to unify the mobile world around one platform (Android, the iPhone, the Open Screen Project, Windows Mobile), having the platform which already has a lot of reach and momentum become an open source player is a big, big deal.
The list of companies making up the new "Symbian Foundation" is significant. It includes carriers like AT&T and NTT DOCOMO, handset manufacturers like LG Electronics and Motorola, and Samsung, and other parties like Texas Instruments and Vodafone. In general it's a wide array of companies that has broad coverage of the market. And any company can join.
Right now the Symbian operating system has about 60% marketshare, which is a huge number in the fragmented world of mobile devices. For developers, this is very significant. Right now for people creating mobile RIAs it's kind of a toss up as far as which platform to go with. Do you build for the hot new iPhone and stay locked into Apple, do you bank on Adobe getting Flash up to par with the desktop player and getting penetration on a bunch of phones, do you go with the unproven Android platform, or do you go with the open source technology that has 60% of the market. Seems like kind of a no brainer to me, and I think a lot of people building mobile RIAs will agree.
I'm not sure what the development model - especially for user interfaces - looks like on Symbian but I've heard stories that it's not ideal. Currently there are a lot of different implementations of the Symbian platform which is another reason it's been difficult to build for. This will unite those into one platform which will make it more appealing for developers - which is the end goal.
If you're building mobile RIAs then you've got a lot to choose from. On one hand, it may be frustrating, but on the other hand, you've never been a hotter commodity. Everyone wants what you're creating so you can leverage that to get feature requests implemented, get better documentation, better SDKs, or whatever it is you want. Go to town and have fun - you're on the cutting edge.