I noticed that most questions on Money SE fall into the categories
- financial investments
- real estate
If you think about it, these categories, though distantly related, are really very different. There are many subsites on SE that are much closer related with each other.
I understand that traffic plays an important role and there just might not be enough interested users at this moment to allow the creation of subsites. But to just throw it all in one common pot doesn't seem right, too.
I don't know if it's even technically possible but if it is, I would suggest that each question must be qualified as one of the above mentioned categories (plus "other"), and that questions on taxes need to have a country or at least region tag. Those few tags should be available on the starting page of Money SE for filtering. Because if half the questions page is filled with very US specific tax questions, non-US people might feel they're in the wrong place.
Hope this makes sense.
P.S. The tags don't have to be made mandatory per se. But if their use is suggested and the starting page would show the filters, as I've seen on other SE pages, users might be inclined to use them to their own advantage.