For example (just as rough proof of concept)
Research articles: Pretty much any academic library website for published stuff, arxiv.org for white papers in computer science and math, pubmed for biosciences
audio equipment: gearspace.com
Encyclopedia: Wikipedia
Thesaurus: Wordhippo.com
The idea is to avoid needing to visit a search engine. Might be a high idea.
With the decline of search, web banners could come back in style!
Web rings are eternal!