You could put your directory URL on pens and refrigerator magnets. It helps to jhave a catchy directory dot com name that people rember though so they will remeber to type it in correctly.
In considering off line market, perhaps one should remember the fate of many dot.com boom/bust companies , circa 1997/2000 One problem they had was keeping their names in the publics eyes, They spent cartloads of money on marketing, but the money disappeared as fast as the made it, then faster than they made it Till fairly recently, only Ebay & Dell made real money online, then along comes Google Making money in a market where Yahoo was just surviving Why ?