A fanlisting is simply an online list of fans of a subject (in this case for cecil harvey) 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. Fanlistings do not have to be large sites (although some are), they are just a place where you can sign up with other fans. TheFanlistings.org is the original (but not official) web directory for fanlistings, dedicated to uniting the fans.
Description from tfl.

cecil

I know I know I promised a mini-shrine even here. Just give me the time to move all my sites from the old domain, and I'll probably add this section before the end of October!