Please allow 7zip (.7z) for file attachments. In some cases the file size savings are dramatic. Just right now, I have a folder of about 70+ .bins that take up 2.1 MBs in rar, and only 28K total in 7zip. This is because both rar and zip are stupid and don't check for interfile similarities. The 7zip compression format benefits the user with convenience, and the site admin with bandwidth costs.