The Microsoft news is coming thick and fast. A few days ago we discussed Office for iPad, Microsoft’s confession of unethical behaviour and its release of MS-DOS code under a prohibitive license. This weeks news seems even bigger: open source for .Net and $0 pricing for mobile Windows. There’s cause to be excited, yet as ever caution is required.

The excitement comes from the .Net news. The formation of the .Net Foundation and the hosting of 24 projects within it should liberate developers to innovate in a way that seemed impossible under previous leadership. This move has seemed an obvious one for the open source community for a long time, as it offers a new lease of life for .Net through contributor innovation and should help create a rich, monetisable market.

The caution relates to the news that Windows for mobile will be free of charge. Whilst unarguably a big move, it’s not open source — the license terms still restrict how you can use the software. This is important, as whilst a “first hit is free” approach to getting people using mobile Windows might bring some results, the key to sustained innovation and therefore sustained increase in the user base comes from removing the need to ask for permission before you can innovate.

Read Simon’s full analysis in the InfoWorld article.