If we consider that the so–called “real world” is simply an example of worldbuilding which has already been done, and is being done every day, then it works.
To put it another way: if the question concerns the worldbuilding of a world which happens to resemble the “real world”, then it is certainly topical.
My caveat:
It does require that a question be formed with such or similar an attitude; if the question tends to veer more towards Social Change or Social Engineering Stack Exchanges, then it is probably time for an Area 51 proposal.
Ergo:
This is for fictional worlds. Their resemblance to the “real world” is irrelevant.
- If the questions asks how to do something in the confines of a certain system, then it is not worldbuilding — even if that system is a fictional world.
- If the question asks how to change the confines of a system, or how to project the state of a system expanded through time or space or any other dimension, then it possibly is worldbuilding.
Even if it is requesting for a future state of a system which is indistinguishable from the “real world”, it should be accepted here — so long as it meets the other criteria. E.g. asking predictions for the outcome of an election for the succeeding year could be topical here: such a thing could, conceivably, be used for building a fictional world.