For a retail business that sells the same products every day? Not so much. (Altho I'm sure that the insider's tip of a sale – including the opportunity to enjoy the sale before it is open to the public – would be welcome on many levels.)
But for a retail business that offers services in addition to products, social media can be very helpful.
For instance — a store that sells wool for knitting and rug-hooking, and offers classes to teach people how to knit and rug hook… beginner classes, advanced classes… or offer one day seminars with a reputed expert in the field… or offers special evenings where a group can get together for a social evening while they knit… or if they receive a hot new product that people have been waiting for or a new line of patterns.
For a small cafe with high repeat traffic — a daily tweet of what is on special may be welcomed information.
As with any type of advertising — it is all about the relevancy of the message.
If a business is constantly contacting me, they'd better have something to say.