As far as Immutable Coffee being a Stack Overflow replacement, I don't think that's accurate. Stack Overflow is already saturated enough that I don't think that there's any need for another website to exist for posterity's sake. Being able to google questions and answers doesn't feel like a very important goal, especially considering how quickly answers get invalidated with how fast programming moves anyway.
As far as it being a side-gig for open source developers, I think that's an accurate assessment -- unfortunately. I did try very hard to do something that sets this site apart from traditional freelancing, and that's in the quick pace which a developer can answer questions. It doesn't take much time at all to log onto IC and really quickly claim a few questions and start helping people, in contrast with how long it takes to set up traditional freelance gigs.
Thanks for believing in the mission! I have a few other ideas that are in the works with regards to this as well, that I'm just as excited to show HN.