.ftpaccess
A .ftpaccess file is meant to function like Apache's .htaccess file: a file that acts as free-floating section of the server's configuration file. If a .ftpaccess file is present in a directory in which ProFTPD performs some action, ProFTPD will parse that .ftpaccess file as a configuration file, and act accordingly. Note that only some configuration directives are allowed in the .ftpaccess section, though.
.htaccess
The advantage of having this capability is that users can customize how the server treats directories that are under the user's control, by using files placed in those directories, instead of allowing the user to modify the main server configuration file itself. The disadvantage is that a user is capable of possibly overriding a configuration value that was set in the main configuration file for a specific purpose.
ProFTPD treats a directory that contains a .ftpaccess file exactly as if the configuration directives in that file had been placed in a <Directory> section in the main proftpd.conf file. For example, if there is a /home/users/bob directory on your system, and in that directory there was a .ftpaccess file that contained:
<Directory>
proftpd.conf
/home/users/bob
DirFakeUser on ~ DirFakeGroup on ~ Umask 0077
<Directory /home/users/bob> DirFakeUser on ~ DirFakeGroup on ~ Umask 0077 </Directory>
The AllowOverride directive can be used to disable ProFTPD's support for .ftpaccess files.
AllowOverride