For example, if I want to reach a wider audience of potential answerers, is it acceptable to post the same question here, as well as on mathoverflow, and other sites that come up that are relevant? Or is that considered a mild form of spamming?
. This is making chaos and irritates the answerers.
If you are sure that the question is relevant on two SEs, it probably can be split in two separate parts with a gain in clarity.
If you are not sure which place is more adequate, try on one site and let its community decide whether to keep it or migrate to a more suitable site.