Another question intended for Main was just asked here on Meta:
I suspect part of the reason askers of such questions think they have found the right place is because it accepts a meta tag of qgis and they think that it is a normal tag.
Is there any reason why we need a qgis meta tag here on Meta, or should it be burninated?
There are no tags for other GIS software products and companies. I recall that there were a few at some time in the past but I think they were burninated long ago.