New Producers
There are great examples emerging of libraries acting as new producers, but I think they are still the exception rather than the rule. Ideas such as podcasts of story times, blogs to support book groups or gamers, etc. allow the library to produce content relevant to the community it services. I see the production arena as one where the library can really step up and reach out to the niche populations because the software tools are so inclusionary.
New Markets
Certainly, a library is probably one of the purest and oldest forms of an aggregator going. While once only books were contained in libraries, today libraries can be seen as an aggregator of aggregators--books, music, films and information in the form of reference librarians, online services and paper displays (e.g. tax forms) are found in the library. In addition, the library acts as a community center providing a place to meet and discuss ideas.
With items such as downloadable audiobooks, eFlicks, music, and other digitized content, and the service provided by interlibrary loan, libraries are moving away from their dependence on physical space alone. Interestingly, Borders has decided to move further away from the long tail
and decrease inventory in stores to allow more titles to face out. While I think it is a worry that Amazon will one day rule the book world entirely, at least the library still has the distinct advantage of being free! However, libraries must capitalize on the long tail distribution services they can provide.
New Tastemakers
Reader's advisory is probably the most obvious way librarians act as tastemakers. Although I don't work in a library, I know that when I provide a book recommendation through my blog, or somehow match an information need with the desired information, nothing is more satisfying to me. Filling those needs is probably what got me interested in librarianship in the first place.
While no librarian can be an expert on all genres of books and music, librarians hold the keys to the filters. It is their job to be able to help patrons who have both popular and niche interests find what they want. Librarians act as pre-filters through collection development, but by paying attention to the post-filters (through patron word of mouth, blogs, reviews, etc.) they will provide a higher degree of service excellence.