While the many Linux groups are trying to push the mobile market, Nokia has taken Symbian OS open source (via Matt Assay), under the Eclipse License. The Symbian Foundation will push Symbian as the most proven, open and complete mobile software platform.
This is big news, from multiple aspects. Symbian is already the dominant OS in the mobile market. Opening it up will lure in a lot of developers and businesses to perhaps adopt it in new ways.
Having said this, being a favorite in open source needs more than just the license. It will be interesting to see how the community is built around it and how is it treated. That will be the key in retaining the dominance in the mobile market against Linux.
Either way, it is a good news for the users. We now get more transparency and say into products that we already use. It also opens doors for more potential in future.