Save yourself some trouble, and be considerate of what kind of content you serve to both customers and those who haven’t become a customer yet. 

You have much more control over this through 'social selling'. 

How frustrating is it to buy something only to see a coupon for said item after the fact?

Whilst there are many forms of content campaigns that can annoy us, the worst one for me is the 'retargeting' after I've actually made the purchase, you know the ones, hotel, train, flight etc, I then get followed around the internet for days, sometimes weeks with the offer that should have been available at the time I booked.

From a content strategy perspective, consider it a best practice to avoid publishing redundant promotions to people who've already converted, and can't utilize them. I came across this article (link below) that looks to highlight the 8 most annoying things about content strategies.

The starting point for producing consistently good content starts with a well defined strategy combined with internal alignment on the outcome. 

We often see companies who are happy to re-work the corporate message, or product promotion and try to dress it up as 'content'. They think that people might be interested in it, they have it in the 'content' library so why not reuse it? - its all a bit lazy, and smacks of insincerity, authenticity, and strategy.

We see that its all about tactics, when it needs to be about audience focus, and measurable results. 

I'm currently 'socially' bench marking a very large UK/US based B2C retailer, it seems that they're using social media for either an intranet to the rest of the employees (fair enough I guess) or to carry over the 'advertise and promote' mentality for their products. 

They have lots of followers, they also have lots of employees, so we can't tell where the 'real' fans are. They don't seem to produce the type of content that's designed to engage existing customers, if it was, and they had the right 'social listening' tools they would 'learn' things that would add to that focus and direction, they might even learn how to 'entice' the competitions customers towards them.