First ... I would imagine that attachments are stored in the file system, yes? Does xF have the ability to redirect attachment links to a different URL, i.e. attachments.myserver.com vs. forum.myservers.com? Second ... maybe it would be a good idea to implement some sort of file fingerprinting in xF? I see many new file/archive solutions these days fingerprint a file and essentially only keeps on version of a file. For example, if Bobby uploads a image file it checks to see if the file is already on the server by analyzing a fingerprint of the file and matching it against files that are already in existance. If the file already exists, it just puts a link to the file that is already there. If the file doesn't exist, it uploads the file. This should help cut down on wasted stored space by users who insist on uploading the same file multiple times.