There are two types of Internet accesses. One type is the shell account access. The other is the PPP/SLIP account access.
Most on-line services, like CompuServe, America On-Line, and Prodigy only offer shell accounts. With a shell account, the host computer is a member of Internet. The client computer, however, is not a member of Internet.
Internet service provider like Smart.Net, Clark.Net, and Charm.Net offers both shell accounts and SLIP/PPP accounts. With SLIP/PPP access, both the host and client computers are members of Internet.
With shell account access, client computers can only be used as computer teminals. The software running on client computers only provide the user interface. The actual internet access applications run on the host computer.
Since the client computers are not members of Internet, they cannot use this type of Internet access to establish Wide Area Networks (WANs).Because client computers with SLIP/PPP access are full members of Internet, they are not restricted to using the internet access provider's user interface. They are peers among all other internet members, capable of sharing data and processing resources.
With SLIP/PPP access, client computers can establish Wide Area Networks (WANs).