Your first question is probably something along the lines of, "What in the world do a bunch of nerdy fans have to do with folklore?" The answer? More than you think.
In Living Folklore, Martha Sims writes about fans of Japanese animation or manga as a folklore groups, but acknowledges that many other fan groups start and convene in much of the same ways or traditions.
"Like fans of particular types of music, fans of other popular entertainments seek out space where they can share and express their interests. Those interested in music can still visit the record stores, but often they turn to the Internet to listen to and learn about the music and performers they enjoy. Similarly, many other fan groups meet, grow, and evolve almost exclusively online, and their in-person interaction is secondary to their online identities, if it occurs at all."
In Columbus, Ohio, many traditions are celebrated and would be considered folklore by almost anyone who talks about them. Oktoberfest, the Renaissance Festival, or the Asian Festival are all calendar customs in which groups of people with similar heritages or cultures or even just fans of the type gather together to celebrate food, drinks, and friends. In this sense, things like Comic-Con and other fan conventions are no different.
My goal was originally to present Star Wars fans as a folklore group, but fandoms extend so far beyond that particular story line that it seems a shame not to include them all. Please feel free to browse around and read through the data I have collected. Maybe you'll even learn something new!