Ancient cultures may have their shamans, but modern culture has some unusual roles emerging as well. The cultural curator role has expanded enormously, with both professional and amateur versions. People with Pinterest boards, many blogs and blog-like content sites are not so much new content as they are curated content -- the curator shares their taste in something, sifting and sorting what they find into consumable information bits for others.
There are certainly paid cultural curators -- they hang out in journalism in the fashion pages, they may be professional speakers, or even celebrities in their own right. (An example isn't popping into mind right now, but perhaps Gwyneth Paltrow would be pretty close. Although she was a celebrity for skills other than her opinions about taste.)
A role that is not much talked about is the explainer. Explainers are not experts in the fields they explain, so much as they are interpreters of difficult material that the rest of us can then digest. Malcolm Gladwell is the standard carrier for this breed. I encountered a delightful example of explaining in James Gleick's blog, Around.com.