Making a business of the bit buffet

SELLING access to the Internet looks easy enough. The number of customers, already in the tens of millions, is doubling each year. Providing them with some software, a telephone number they can dial from their computer and a link to the Internet is so simple that a technically literate teenager can offer such a service from a bedroom--as some have. For that, you can charge customers $240 a year, more than most spend on their local telephone bill. The Internet service industry earned revenues of $1.4 billion in America alone last year, an amount that is expected to rise to nearly $30 billion by 2000.