I was wondering if there is a viable place on Stack Exchange to ask economics-related questions. Questions I'd have in particular could be equation-based or theoretical. I suppose the equation-based questions could possibly fit into mathematics but I haven't checked their FAQ.
Update: Economics is back!. For pure economic theory and its implication, that is the site to go to.
That said, there are other sites to consider, as my previous answer showed.
While Economics Stack Exchange is, alas, no more, there is some overlap with existing proposals.
has a certain amount of scope for macroeconomic issues. Because Politics deals with policy questions as being on-topic, we often use economic theory to explain policy choices. Understanding the exact nature of key macroeconomic players (Federal Reserve / Central Bank for monetary policy, Legislatures around the world for fiscal policy) is also on topic. What is excluded is pure economic theory for its own sake.
NOTE: Politics is particularly friendly towards macroeconomic questions
tolerates what I would call concrete Microeconomics. While legal issues and pure economic theory are off-topic, there is some scope for understanding the incentives that drive individual financial decisions. Time Value of Money / Present Value, Tax incentives, and the like seem to fit. While personal choice and rational actor theory is typically well received, pure economic theory is usually not.
Quantitative is more geared to finance, but a lot of economic theory goes there too...
often has scope for historical economic data questions.
discusses the logical implications of logic topics like game theory.
Beyond that, as stated, Area 51 occasionally has Social Sciences and economic SE proposals, but the critical mass rarely seems to gather to tip them over the edge.
There seem to be two new related proposals, Economics and Finance & Economics that may be worth following. From the current sites, Mathematics and Personal Finance and Money may be close to what you are looking for, depending on what your actual question is, but please make sure to read their FAQs and search for similar questions before asking.
There is now a new Economics.SE beta which you can access at https://economics.stackexchange.com/.