In the mid-1970s, U.S. telephone companies began adopting metered service pricing for telephone directory assistance.  Previously, unlimited free directory assistance calls were allowed under the flat rate for local telephone service.  The new pricing structure had a fixed allowance of free calls (typically three to five) and a per-call charge for calls above that allowance. [...]

Telephone companies operated the first network-mediated, mass-market information search service.  It’s called directory assistance.   Make a telephone call, voice a query, and get back relevant information. By some narrow metrics, U.S. telephone companies have quite successfully developed this information search business.  Prior to 1974, directory assistance in the U.S. was a freely offered ancillary service [...]

Unlike the telegraph and Morse Code, the telephone enabled communication in ordinary spoken language.  The telephone thus lowered transactions costs for conveying information quickly across space and created better opportunities for entrepreneurs to offer new information services.  Here’s an example of such innovation: Several years ago [about 1902] an editor in a small Illinois town [...]