Using text code 67076 instead of their phone number, a real menswear store I've never done business with sent me an ad.  I looked up the code and found out that texts from 67076 are through CallFire, which is an "opt-in notification system for emergencies, employee alerts and opt-in business-related notifications. CallFire SMS Service is a cross-carrier double opt-in messaging service designed to allow small businesses to alert their customers."  I never opted in to receive any retail ads.

That code is reported on this site as being connected to scams.  I haven't seen anyone here say that a legitimate business contacted them through a text from 67076, which is a shared short code.