I started looking at the Hidden tag when I answered this question: Can I hide using Cunning Sneak with Wilderness Skirmisher?
To me it seems that stealth (a much more widely used tag) would make more sense than having a hidden tag which is overly specific. Tagging a question with both 4e and stealth would include everything that the hidden tag connotes while also having a wider subject matter and both the stealth tag can be applied to non-4e questions whereas hidden cannot. Thoughts?