NCSA HTTPd allows you to create HTML catalogs of your directories, in order to tell users what's in them.
I have another directory whose contents are constantly changing. I don't really want to write and maintain an index. In this case, HTTPd will generate an index of the directory for me when a user requests the directory. I can configure HTTPd to ignore certain files, to give a certain icon for certain files, to place a short description after file names, and include either an HTML or plaintext README which tells people what is in the directory.