It's a retarded phrase. It means Over The Counter and refers to the tobaccos that you get at the drug store/grocery store like Prince Albert, Half and Half, Carter Hall, Middleton's Cherry, Borkum Riff, Captain Black etc. The mass market tobaccos.
Two things make it retarded in my book. One, all tobaccos are over the counter, I mean do I really need a prescription to get Lane's 1Q or Dunhill 965? No, I just need to go to the Tinderbox at the mall. Two, you can't even find OTC tobaccos anymore at the drugstore. Seriously, have you been to a CVS or Walgreens? CVS stopped selling tobacco and maybe your local Walgreens will carry a pouch of Captain Black and their house brand Blender's Gold but you aren't going to find Granger or Velvet on the shelves.
You can sometimes find a few of these brands at a discount cigarette store but barring that you're going to have to mail order it just the same as you would Escudo or Three Nuns.
People crap on these tobaccos because they are snobs who think world starts and ends with virginia tobaccos and orientals. Burleys are feces in their eyes, only fit for chewing and cigarettes. These are the same people that drink single variety Arabica coffees, god forbid someone make a blend with a little robusta in it. They make me sick. It is pure snobbery which causes them to bad mouth burleys.
Most of the "OTCs" are burley heavy. Also most aromatics are burley since burley is a little more neutral in flavor and absorbs the flavored casings and toppings better than virginas. All the more reason for the snobs to crap on burleys.
What really gets me is the intense anglophilia that exists in the forums. All these snobs smoke English tobaccos while reciting the purity laws and worship at the alters of Dunhill, Charatan and Sobranie. Psst, hey fellow pipesters, I want to let you in on something. We had a little war with these guys about 240 years ago. We kicked the limeys out of America once and for all. It's over. Why are you guys longing for the colonial days smoking your latakia blends, watching your Monty Python reruns and overpaying for Dunhills turned in Spain? Get over it. We are Americans, now smoke a drugstore burley or American Aromatic and goddamn act like it. Its time again to knock the brits off their pedestal.