This relates to the fact that Stack Exchange is hosted on a Windows platform. It is indeed worrying that a communication platform of a community focused on free software relies on proprietary software. Apart from this, what worries me is the availability of the data, that is, all the knowledge accumulated on askubuntu (all questions and answers on this site). I know that all user generated content is licensed as cc-wiki but this is not what I'm getting at. I wonder what happens if SX is shut down or if its decided that Ubuntu's Q&A platform is to be hosted in another place or be handled in any other way. Is all the data generated on this site freely available so that it may be transferred to another platform?
In short: Is there any reason to worry that this site's information and community are locked in – or that they run the risk of getting locked in – because of Stack Exchange not being free software?
The site's content is licensed as cc-wiki and will always be such. Data dumps are available every months and efforts to make these more real-time are underway. The platform is free and will always be free to use. The infrastructure running this free platform is indifferent because the content and platform are free and always will be.