I was recently looking for an old post on gaming.stackexchange.com, and one of the things I remembered was that the game "SingStar" was mentioned. Thus, I typed "singstar site:gaming.stackexchange.com" into google, expecting to only see a dozen posts or so. Instead, I was greeted with hundreds of PAGES of results:
Only one of the shown results is an actual post.
Having the tag-wiki page indexed makes sense, and maybe the tag-FAQs. However, the tag search-pages are just noise, especially the ones which combine Tag1 + Tag2, for every possible combination with a question. I think these should be marked with a noindex.