Name that domain
by Amanda C. Kooser
While.com is still the most dominant top-level domain, other options are still being introduced. New entrants .postand.travel will be joining the ranks alongside .org, .net, .biz, more than 200 different country codes and a few miscellaneous others. Negotiations haven't been finalized and could drag on for several more months, but entrepreneurs who are still seeking easy-to-remember domains should have these new options available before the end of the year.
The Internet Corporation for Assigned Names and Numbers is also looking over applications to create other top-level domains such as .eu and .jobs. Still, it's hard to shake the reliance on the ubiquitous .com. According to a report from internet domain-name registrar VeriSign late last year, total domain-name registration hit an all-time high. If .post or .travel fits your business, you might want to consider jumping onboard when they become available.
reference : http://findarticles.com/p/articles/mi_m0DTI/is_3_33/ai_n11836459
Overview Domain Name
The most common types of domain names are hostnames that provide more memorable names to stand in for numeric IP addresses. They allow for any service to move to a different location in the topology of the Internet (or an intranet), which would then have a different IP address.
By allowing the use of unique alphabetical addresses instead of numeric ones, domain names allow Internet users to more easily find and communicate with web sites and other server-based services. The flexibility of the domain name system allows multiple IP addresses to be assigned to a single domain name, or multiple domain names to be assigned to a single IP address. This means that one server may have multiple roles (such as hosting multiple independent Web sites), or that one role can be spread among many servers. One IP address can also be assigned to several servers, as used in anycast and hijacked IP space.
Hostnames are restricted to the ASCII letters "a" through "z" (case-insensitive), the digits "0" through "9", and the hyphen, with some other restrictions. Registrars restrict the domains to valid hostnames, since, otherwise, they would be useless. The Internationalized domain name (IDN) system has been developed to bypass the restrictions on character allowances in hostnames, making it easier for users of non-English alphabets to use the Internet. The underscore character is frequently used to ensure that a domain name is not recognized as a hostname, for example with the use of SRV records, although some older systems, such as NetBIOS did allow it. Due to confusion and other reasons, domain names with underscores in them are sometimes used where hostnames are required.
