Domain extensions are the top most part of a domain name. A domain name is the characterizing feature for identifying, naming and creating an address for a website on the internet. All domain names are developed using the guiding principles of the Domain Name System.
Each domain name consists of dots that separate each part of the name.
For example the Web site compnetworking.about.com has three parts; from the lowest to the highest level. The first part (‘compnetworking’) refers to a specific website. Secondly (“about) identifies the organization domain and lastly (‘.com’) points out the top level domain (TLD).
Domain names are organized according to levels. The first levels of domain names are the most prominently used. There are second level and third level domain names reserved for access to the internet via local networks and making internet resources publicly available. Each of the domains used must be registered by Domain Name Registrars.
Not only do domain names/ extensions allow the recognition of a website it also indicates who owns and has authority for the site. This is an essential function for domain extensions because they make internet resources clearly recognizable and easy to remember.
The major top level domain extensions used in web addresses are as follows; .com, .org, .net, .edu, .gov, .int, .mil and .org. There are also Country level top domains such .fr for France or .jp for Japan which may simultaneously utilize intervening domains such as .co or .org.
Multiple sub-domains may be created in conjunction with major domains. The possibilities thereafter become endless but the domain created is a subset of the main one. There are also special group of alternative top level domains which are authorized by the Internet Corporation for Assigned Names and Numbers (ICANN).
Due to their flexibility and obvious benefits, it has become increasingly popular to develop multiple sub-domains which do not necessarily correspond with the intended purpose of the top level domain. Therefore the structural relationship which should exist between top-level domains and their sub-domains is diminished. For example where an organization has a top level domain, sub-domains created should reflect departments or subsidiaries of that organization however, the practice is the opposite. Sub-domains created aren’t always correspondent to their respective top-level domains. This attempt to utilize the existence of one to market their service via the internet, though that service may have no bearing on the main domain it is done with the view of making sites more memorable, appealing and convenient for users of the internet.
To combat this abuse of trademark rights, laws like Anti-cyber-squatting Consumer Protection Act in the US and Trademarks Act in India were developed to mitigate non-compliance.