some definitions:
SMM - social media marketing
Faux Pas - goof, blunder, oopsie! (sorry, it's French)

The greatest faux pas I see on the social networking sites is this:
A COMPLETE AND UTTER MISUNDERSTANDING OF HOW TO FLIRT:
I get people who I follow INSTANTLY (with their auto-bot of course) hammer me on the head with their deal, or their blog, or their special widget - whatever
So, they are bringing all their bad OFFLINE habits into the cool, new SMM environment, and, uh, SURPRISE!! It DOESN'T WORK IN HERE EITHER!
People need to learn IFM - Internet Flirt Marketing. Brand development, PIF (pay it forward), creating content, ADDING VALUE to the conversation, instead of "hey, get 16,000 followers in the next 90 minutes with...."
It makes me sad - the industry remains one of a near TOTAL LACK of proper training, even with all the magnificent (and nearly free) tools we have at our disposal.