Yes, within reason. Relevant tags are extremely helpful in helping search engines find our content.
However, it doesn't matter currently, as HP has taken control of generating tags--something I'm not altogether happy about. I wonder if there are work-arounds for this? My suspicion is that automated methods are not going to be an altogether satisfactory substitute for knowing the subject matter.
On the other hand, I do think that in doing your own tags you can easily overlook the obvious. Perhaps HP should allow us to select a certain number of tags, then let their process, whatever it is, do its work.