A business that provides its subscribers with a wide variety of data transmitted over telecommunications lines. Online services provide an infrastructure in which subscribers can communicate with one another, either by exchanging e-mail messages or by participating in online conferences (forums). In addition, the service can connect users with an almost unlimited number of third-party information providers. Subscribers can get up-to-date stock quotes, news stories hot off the wire, articles from many magazines and journals, in fact, almost any information that has been put in electronic form. Of course, accessing all this data carries a price.
The difference between an online service and a bulletin board service is one of scale and profits. Online services provide a variety of information and services, whereas BBS's normally concentrate on a single theme. In addition, BBS's are often operated on a non-profit basis whereas online services are always for profit. Three of the largest online services are America Online, Compuserve and MSN.