http and www
posted 8 years ago
See the Wiki on Domain Name for the details, but the third-level domain name (the "www" in your example) is used to designate a particular server (i.e. "www" for World Wide Web, or HTTP, "ftp" for the FTP server, "mail" for the mail server). Since the most popular service is HTTP, it has recently become popular to just use the second and top level domain names "domain.com" rather than the often redundant "www.domain.com"