Ask HN: Internal StackOverflow for a large company. Penny for your thoughts

I work for a fairly sizeable software house (~1.5k employees, a large percent obviously being developers).

While plenty of communication systems are used within the company, I'd really like to lobby for launching an internal StackOverflow Q&A, for the sake of facilitating knowledge exchange.

My reasoning is that the gamification of the process - reputation points - would be a significant encouragement.

Some of the usecases I imagine would be

* troubleshooting (obviously nothing stops anyone from crossposting the question on "regular" StackOverflow; the question would have better visibility on the internal site though, plus the "same boat" factor, plus no concerns about leaking our client's data in some way);

* library / tooling recommendations; or anti-recommendations;

* follow-ups after internal seminars.

(I'd assume moderation not as strict as on the real SO, allowing for a tad greater subjectivity).

I believe it would be a much better and "alive" format than, say, an internal Wiki; owing to its democratic nature and lower involvement threshold.

Have you had any experience with such solution, in a similar context? What were the takeaways? Did it work? Or what made it fail / get nipped in the bud? What were the unforeseen pros and cons?

On the same note - any suggestions regarding the software on which to base it, if it's worth pursuing?

Stack Overflow Enterprise would seem to be the go-to choice, but there are plenty of open-source clones as well: https://meta.stackexchange.com/questions/2267/stack-exchange-clones

Any insights would be very appreciated.