This question https://blender.stackexchange.com/questions/13737/best-way-to-model was migrated from game dev with the tag of untaged. Is there any way to retag that question now? On most closed questions there is still the option to edit them, why is this question locked? I would say that this question could be deleted all together, but again for some reason it is locked.
I'm not exactly sure why you can't edit it (I can as a moderator). It's probably because it was migrated then closed (?). Every question needs at least one tag, so what probably happened was that when the moderator from GD.SE migrated it he dubiously selected the untagged tag.
It's a good idea to keep closed questions around. They help show the community what's not accepted here. (Unless if it's spam, etc, of course).
If you want it changed, let me know. I guess the modeling tag would work.