So, what actually is a "fanlisting"? It's literally in the word - it is a listing of fans. This is a common concept, but it was popularised into an online phenomenon by the creation of the unofficial Fanlistings Organisation (TFL) in 2000, and has now expanded to listing thousands of diverse fanlisting subjects. Below is a slightly altered definition from the original headquarters, TheFanlistings.org:
A fanlisting is simply an online list of fans of a subject, such as a TV show, actor, or musician, that is created by an individual and open for fans from around the world to join. There are no costs, and the only requirements to join a fanlisting are your name and country, and often e-mail. Fanlistings do not have to be large sites; they are just a place where fans can sign up their names to an online list. TheFanListings.Org is the original online fanlisting directory.
And this is the only fanlisting checked by and listed at TheFanlistings.Org (TFL.Org) for the Blues, in the "Music Miscellany" category, and then the "Genres" subcategory (check at this page). However, this website is only recognised by TFL.Org - not by any official, profit-making, monetary organisations centred around the Blues or otherwise. In short: I MAKE NO MONEY FROM THIS WEBSITE. It's voluntary, and it's all about the love. :) For a full disclaimer, please click here.
Anyway! TFL is a great community, and what's so wonderful about it is that anyone can be a part of it - as long as you're a fan of something and can share your love, you're in! There is a detailed introduction at this link if you are a beginner, and want to get involved. :) I'd definitely recommend it.