From the Skyfire blog:
We are announcing that we will complete the phase out of our legacy v1.0 product on Windows Mobile and Symbian on December 31st, 2010 for remaining countries. This two-year old product used a “proxy browser” approach which is no longer our vision. It was a revolutionary product when introduced and offered for free, but the fast-moving mobile market has changed significantly since 2007, and as a small tech start-up, we need to keep innovating forward.
This was a very difficult decision for us. We put our hearts and souls into the 1.0 product and greatly value the many Skyfire fans who used the product and provided us with invaluable feedback during this intensive research & development phase of our company. We experimented with ways to charge for the product (in certain international test markets) so that existing Windows Mobile and Symbian users could continue to use the service, but the payment mechanisms were very cumbersome and the piracy rates were so high on those OS platforms that we could not make it work. More importantly, we faced a decision point: If we were to begin charging money for a product, we had to commit to multiple years of support and enhancement of the product. It would not be the ethical thing to do to start down that path, given that we would not expect enough revenue to make that sustainable on the legacy 1.0 product, and we can no longer subsidize it. The right thing we decided was to focus on 2.0 and beyond.