I've noticed that when the administrator deletes a member, neither the member subdirectory under the uploads directory nor the files that have been uploaded by that member (avatars, photos etc) are deleted. I can see this being a problem with the app eating up disk space over time.
I've searched the forum and can find no reference to this elsewhere.... has someone done a MOD for this? If not, it shouldn't be too hard to add some code to delete_member.asp and batch_delete_members.asp to use the filesystem object to delete the directory for each member to be deleted. I could give it a shot.