The Worldwide Web makes a far better advertising medium than does this mailing list. An example of a commercial post might be a list of items available, with their prices and a phone number to call. This list is not and will not be gated to any Usenet newsgroup. Reposts from any rec.radio. Check your documentation to ensure that you are not sending out HTML, RTF or other versions of every message.
Many subscribers pay a fee to download their mail.
It would be unfair for them to have to pay to download 50k of uuencoded .WAV files no matter how interesting those files may be. This is a hobby. Single quotes around a command should not be sent, but are there for clarity. If you run into difficulties, please contact your ISP first. The majority of problems involving subscriptions to SCAN-L or other lists can be traced to incorrectly configured mailers.