Email is the most popular, and probably the most productive, resource available on the Internet.
The ability to send messages electronically to users around the globe has made it seem smaller, enabling millions to share information. Many sites on the internet today provide free email for anyone who wants. Email servers interact with one another using SMTP - or Simple Mail Transfer Protocol. It's a protocol that regulates data tranfers and routing of messages between mail servers. A computer need not be connected directly to the Internet to send and receive email from other Internet users.