Now this is not scientific, and it is not necessarily significant. Tips 'n Tricks and Troubleshooting could be calendar-specific at times and not be cross-classified. And E-Mail does not get a separate specific mention, which would provide the most direct comparison.
All we're measuring is the relative time it's tagged vis-a-vis the other tags. Could be it's not mentioned because it's stable and not a problem (we find a lot of problems here, but that's out specialty), or it could be that other priorities are higher.