In addition to plenty of useful information, America Online offers "chat rooms" where you can have a written conversation with other people in real time. If you meet someone you like, you can even go off to a "private room." These can be used socially, or as a substitute for a business conference call. But their most common use is for romance -- sometimes innocent, often explicitly sexual.

America Online has been growing rapidly, both in terms of the number of subscribers (over 600,000) and in terms of the services it offers. The service set up an Internet mail gateway in 1993, followed by full USENET access in 1994.

Prodigy

Prodigy is the network everyone loves to hate. At a recent talk by Ted Nelson, one of the grand old men of cyberspace, the mere mention of Prodigy got a huge laugh from the audience. The service sells one-fifth of every screen to advertisers, and its unofficial motto is said to be "Shut up and shop."

Owned by IBM and Sears, Prodigy first became notorious for censoring its discussion groups. In their effort to maintain Prodigy's "family" status, censors deleted anything Queen Victoria might have considered remotely inappropriate. An example: Members of the dog fanciers' forum are not allowed to use the word "bitch" to refer to a female dog.

Eventually, discussion group members started using mailing lists to send private, uncensored mail to their network buddies. With almost no warning, Prodigy started charging extra for email usage, making the mailing lists economically unfeasible for many users. Prodigy's explanation: "We never promised to maintain free email service forever."

For years Prodigy said it would never offer an Internet gateway, but in 1993 it finally broke down. However, Prodigy users are charged not only for the Internet messages they send, but also for those they receive. Users are not thrilled.

Despite these drawbacks, Prodigy has a large installed base -- over two million users. (It's hard to track exact numbers because the service