We have a Stack Overflow and a Math Overflow.
Has anyone thought of setting up a Finance Overflow to discuss derivatives and financial instruments used in banks?
This would be a good Q&A site!
Besides the answers given
There are currently some money-based sites already...have a look at the listing on https://web.archive.org/web/20100413233431/https://meta.stackexchange.com/questions/4/list-of-stackexchange-sites, and scroll down to the "Money" section.
The original question was deleted as it was nowadays referred to as "Stack Exchange 1.0". The official current site list URL is https://stackexchange.com/sites, but it doesn't include a Money category.