Competition in mobile operating systems area is getting stronger. Apart from Symbian OS, MS Windows Mobile family, there are plenty of Linux based mobile platforms: Maemo (Nokia), Open Moko (e.g. Neo1973 phone), LiMo (Vodafone, NTT Docomo, Motorola, Samsung, Nec and Panasonic partnership), ACCESS Linux Platform to mention a few. According to CNN Money ("Motorola Unveils MOTOMAGX Mobile Linux Platform" article), Motorola announced its next generation mobile Linux platform - MOTOMAGX. New platform is supposed to "lay the foundation to deliver new levels of openness, flexibility, and support for third-party applications on Motorola mobile devices". In the next few years, up to 60% of Motorola's handset portfolio is expected to be based on Linux, with the MOTOMAGX platform playing a key role in supporting this strategy.
"Motorola's MOTOMAGX platform is designed to support a broad array of content created by third-party developers. Today, MOTOMAGX supports applications developed in Java ME(TM), with plans to introduce new WebUI (featuring web technology to enable widgets and Web 2.0 experiences) and native Linux application environments in upcoming releases. These three application environments, combined with the relevant tools available through Motorola's MOTODEV Studio integrated development environment, will help enable MOTODEV developers to innovate and accelerate time to market for their applications."

I see that Linux will soon be a major competitor to Symbian and Windows Mobile. If Linux based platforms don't have a program similar to Symbian Signed and complicated Platform Security, they may become better platform for mobile developers (Linux is widely accepted by opensource)... It's also worth noting that widgets have become accepted in mobile world and now are spreading around many mobile platforms.