Impressions
The actual number of people who've seen a specific Web page. Impressions are much more accurate than hits when discerning how much traffic your Web page actually receives. Impressions are sometimes called "page views."

Internet
The vast collection of interconnected networks that use TCP/IP protocols.

InterNIC
An organizaton operated by Network Solutions that controls the registration of new domain names. When you purchase a domain name, the InterNIC will bill you $70 for the first two years of ownership and $35 per year thereafter.

Intranet
A private network inside a company or organization that uses the same kinds of software that you would find on the public Internet, but only for internal use.

IP Number (IP Address)
The unique 4-part number assigned to each and every computer linked to the Internet (e.g., 206.141.202.111). When you connect to the Internet, your ISP assigns you an IP number for the duration of your connection. DNS converts domain names into IP addresses.

IRC
Internet Relay Chat: A method of real time communication, powered by a network of servers.

ISDN
Integrated Services Digital Network: A high-speed connection that sends data over phone lines at speeds of up to 64,000 BPS per channel. An ISDN connection can use one or two channels; at two channels, it provides download speeds of up to 128,000 BPS.