Postal addresses allows people to send you physical documents -- what "netizens" call snail mail.
Your electronic address uniquely identifies you for the purposes of e-mail and other cyber communication. A postal address refers to a physical place you can see and touch; your e-mail address may only give the receiver a clue about your location.
An e-mail address contains all the information required to ensuring an e-mail arrives at the correct address. Addresses are not case-sensitive. Don't worry about upper and lower case letters. The Internet's domain system knows where to deliver the electronic mail.
How does one translate all of the parts if the address?
At the left of the ubiquitous at sign (@) is the user's identification. It may be an abbreviation of the user's name (such as wgibson for William Gibson), or the full name (william.gibson).
At the right of the @ sign is the name of the access provider*; in the case of large organizations, the address may specify sub-divisions of the provider, such as:
The nj2" identifies the single computer, or "host" where the mail is collected.
After the provider's name is an abbreviation for the type of domain; .edu is a college or university, .gov is government and .org is a non-profit organization.
Finally, there are two standards for domain naming: .com, .edu, .gov, or .org. The other operates on a country basis--a two-letter code only when the address is not in the U.S.; and within the United States, a state abbreviation. The challenge in assigning country codes is complicated by political change; most addresses in Moscow, for instance, still carry the designation of su for Soviet Union.
Your electronic address is unique. No other cyberspace user has the same e-mail address. Network Solutions, the InterNIC, makes sure no two access providers have the same domain name* and your access provider makes sure no two users they serve have the same user name or ID.
When you send e-mail, your return address is usually stamped by your e-mail program so that the receiver can easily respond to you. Your e-mail software automatically handles the correct formatting of your address and name. The return address allows the access provider to return the message if there is a problem.
Returned mail shows-up in your inbox with along with a message saying it is undeliverable.
Senders often believe that email is an instant form of communication. Email usually is delivered within seconds of sending it. Sometimes it can be delivered hours after it is needed.
If you don't know someone's the e-mail address, there are specialized directories run by individuals, as well as Web sites with searchable collections of e-mail addresses culled from various sources.
It's easy to use any of the address services, but you must give them your email service to be allowed to use it. Some users are reluctant to do that to guard privacy.