Bookmarking in Delicious

I think tags in general have great potential. Emphasis on potential. Most tags, however, that I have seen assigned seem extreeeeeemely weak.
I think the Nebraska Access website is a great example. I was totally underwhelmed by the tags assigned. For example, "Nebraska" was assigned and certainly, Nebraska is one of the places one can search for when one enters Nebraska Access. But the website is a portal to the United States at large and to a lesser extent, to other countries. It's a huge genealogy tool, but that (genealogy) was not a tag I saw. "Resources" was okay as a tag but "printed publications" is better if one doesn't want to just reuse newspapers and periodicals from the abstract.
I've noticed this in other sites that use tags as well. A novel about Elizabethan England may be tagged "History." Not wrong, but not very specific. Other tags, such as "Great" or "my favorite" are opinions. They are valid, but unless another user knows and trusts the original taggers opinion, I feel that such tags have a limited usefulness.