Signature promotion

What if there was a way to have a promotional line after an employees signature. So after:

Betsy Sue
Branch Manager
Company Ltd.
555.555.5555 ext. 555
123 Fake St.
Somewhere, Someplace
000 000

You had:

Our new optimax server is rich, see more.

And ‘see more’ went to some promotional page.
I wouldn’t see that as spamming or advertising, because you’re already dealing with the business. It’s just a simple way to promote.