I noticed you liked my idea, but which one?!
That's the disadvantage of writing so much! 
1st idea was simply a toned down AS sales pitch in InstaMail. (My favorite since it could probably be accomplished in a matter of programing moments!)
2nd idea was e-mail setup screen that allows user to select among SEVERAL AS sales pitches, presumably at least one of which would be benign or toned down.
3rd idea was for the remote possibility that AS would allow an auto e-mail to be sent completely without any AS sales pitch. (Yeah, right!)
I would like to extend & edit my suggestion for a new AS "sales pitch" in the InstaMail. It's brief, to the point, and definitely soft-sell:
"This winning bid was placed in behalf of the bidder by AuctionSniper. If you would like to learn more about how this service may help you win more auctions, go to {website address keyed with AS user's e-mail address as referral}".
The neat thing about this "soft-sell" message approach is that I think it piques the recipient's curiosity in the service rather than stir up their wrath or resentment! Sometimes it's better to say less than more! In addition, if the AS user's ID is somehow built into the AS link, they can get free snipes if the recipient clicks on the AS link and signs up! So this would ENCOURAGE AS users to use the InstaMail service because of the fair chance of picking up some free snipe credits!
Anyway, thanks for liking my idea, whichever it was!
Jabbergah