It will without a doubt change the business model that Joel has planned for S-ex.com. you cannot charge $129 / month hosting when the exact same software is available for me to install on my own server, let alone the $2500 / month required for me to do so.

I don't want to downplay the functionality within the SO engine, but there feels like there is a big difference between SO and a blog engine in terms of setup complexity and options, complexity that perhaps would explain why sixapart gets away with charging for 'professional' versions and for support of it.

I work for a large bank, which for reasons of data protection (yes, even for developer chat) does not want any conversations occurring outside our network. As such we would only consider an onsite install - the choice between $30000 that Joel wants for an onsite install and the cost of a shared server in our data center - ~$1500 - makes taking an open source solution a no-brainer.

We've replaced a good number of proprietary solutions with open source alternatives, (operating systems, source control, bug tracking, wiki etc.,), being able to address scale issues without considering the license cost is a huge factor in our decision making.

So the real question for me is whether you should change the pricing of the hosted version and to move to opensource sooner rather than later.