If I had a nickel for every time I saw a salt shaker at Starbucks. Wait, no. Then I'd be broke. Even as a salt enthusiast, my mind hasn't stretched as far as considering salty coffee. Apparently it's big in Taiwan. According to the China Daily:
It gives you three tastes. First, you get the slightly salty taste from the cold cream foam, second, the mixed taste of the salty cream foam and hot coffee, third, the aroma of coffee.
Salt reduces the bitterness in coffee, but only in moderation of course. That second pinch might turn it into a salt lick. Jacob Grier of the blog Liquidity Preference gave it a try and while he doesn't actually recommend doing it on a regular basis, "if you're stuck drinking acrid brew at the airport at 5 a.m., then maybe this salt trick could come in handy." Perhaps french fries should start doubling as coffee stirrers?