As we all know, the One True Meta is in the works. Of course, there will be a bit of a scuffle on which post goes where, MSO or MSE. Now I don't know how this shall be implemented, but I have a suspicion that it will relate to stackoverflow.
Unfortunately, a lot of questions get this tag just because the OP was using SO at the time, though it relates to the whole site.
To that end, I suggest we sift through stackoverflow and weed out all the questions which apply to all the sites in general.
Sifting through the questions I've answered on the tag(most of which are bound to be SE and not SO related since I'm not active on SO), I find some good examples:
https://meta.stackexchange.com/questions/129611/where-to-go-if-nobody-answers-your-query/
iPad Stackoverflow user interface problem
And some more, sifting through the tag:
What can I do when a chat room is in gallery mode and no room owners are around?
What say?