In a number of countries, .co (an abbreviation of commercial) is used as a second-level domain in the Domain Name System used to route internet traffic. Domain registrants register second-level domains of the form .co.xx, where xx is the country code top level domain (e.g., .co.uk in the U.K. and .co.jp in Japan).
Countries using .co as a second-level domain include: Angola (.ao), Barbados (.bb), Canada (.ca), Cook Islands (.ck), Costa Rica (.cr), India (.in), Indonesia (.id), Israel (.il), Japan (.jp), New Zealand (.nz), South Africa (.za), South Korea (.kr), Thailand (.th), United Kingdom (.uk) and Venezuela (.ve).
.co is also a country top-level domain corresponding to Colombia. Its current operator, GoDaddy, [1] [2] [3] markets it globally as an alternative to .com. [4]
The domain com is a top-level domain (TLD) in the Domain Name System (DNS) of the Internet. Created in the first group of Internet domains at the beginning of 1985, its name is derived from the word commercial, indicating its original intended purpose for subdomains registered by commercial organizations. Later, the domain opened for general purposes.
The domain name .tv is the Internet country code top-level domain (ccTLD) for Tuvalu. The domain name is popular, and thus economically valuable, because TV also happens to be an abbreviation of the word television.
Neustar, Inc. is an American technology company that provides real-time information and analytics for risk, digital performance, defense, telecommunications, entertainment, and marketing industries, and also provides clearinghouse and directory services to the global communications and Internet industries. Neustar was the domain name registry for a number of top-level domains, including .biz, .us, .co, .nyc, and .in until the sale of the division to GoDaddy in 2020.
.eu is the country code top-level domain (ccTLD) for the European Union (EU). Launched on 7 December 2005, the domain is available for any person, company or organization based in the European Union. This was extended to the European Economic Area in 2014, after the regulation was incorporated into the EEA Agreement, and hence is also available for any person, company or organization based in Iceland, Liechtenstein and Norway. The TLD is administered by EURid, a consortium originally consisting of the national ccTLD registry operators of Belgium, Sweden, and Italy, joined later by the national registry operator of the Czech Republic. Trademark owners were able to submit registrations through a sunrise period, in an effort to prevent cybersquatting. Full registration started on 7 April 2006.
Verisign, Inc. is an American company based in Reston, Virginia, that operates a diverse array of network infrastructure, including two of the Internet's thirteen root nameservers, the authoritative registry for the .com, .net, and .name generic top-level domains and the .cc country-code top-level domains, and the back-end systems for the .jobs and .edu sponsored top-level domains.
.us is the Internet country code top-level domain (ccTLD) for the United States. It was established in early 1985. Registrants of .us domains must be U.S. citizens, residents, or organizations – or foreign entities with a presence in the United States or any territory of the United States. Most registrants in the U.S. have registered for .com, .net, .org and other gTLDs, instead of .us, which has primarily been used by state and local governments, even though private entities may also register .us domains. The domain is managed by Registry Services, LLC, a domain name registry, on behalf of the United States Department of Commerce.
A country code top-level domain (ccTLD) is an Internet top-level domain generally used or reserved for a country, sovereign state, or dependent territory identified with a country code. All ASCII ccTLD identifiers are two letters long, and all two-letter top-level domains are ccTLDs.
.jp is the Internet country code top-level domain (ccTLD) for Japan. It was established in 1986 and is administered by the Japan Registry Services.
.co is the Internet country code top-level domain (ccTLD) assigned to Colombia.

.vg is the Internet country code top-level domain (ccTLD) for the British Virgin Islands. Because it allows registration at the second level, and does not require the registrant to be associated with the British Virgin Islands, it has also been used by piracy related websites such as The Pirate Bay, and video gaming related blogs and websites.
.in is the country code top-level domain (ccTLD) for India. It was introduced in May 1989. It is currently administered by the National Internet Exchange of India.
.ky is the Internet country code top-level domain (ccTLD) for the Cayman Islands. The code was chosen as other possible options had already been allocated. Registration was limited to residents and registered companies in the Cayman Islands with a local address, but this restriction was removed in September 2015. The Cayman Islands also has the international three-letter code CYM and has won a bid to be awarded the .cym domain in a future expansion of the top-level domain space.

.me is the Internet country code top-level domain (ccTLD) for Montenegro.
The Domain Name System of the Internet consists of a set of top-level domains that constitute the root domain of the hierarchical name space and database. In the growth of the Internet, it became desirable to expand the initial set of six generic top-level domains in 1984. As a result, new top-level domain names have been proposed for implementation by ICANN. Such proposals included a variety of models ranging from adoption of policies for unrestricted gTLDs that could be registered by anyone for any purpose, to chartered gTLDs for specialized uses by specialized organizations. In October 2000, ICANN published a list of proposals for top-level domain strings it had received.
Team Internet Group PLC is a British multinational internet services holding company headquartered in London, United Kingdom. Its subsidiaries provide services categorized in two segments: Online Marketing and Online Presence. The Online Marketing segment offers services and products in digital advertising, domain monetization, traffic commerce and product comparison; the Online Presence segment provide domain name registry and registrar services, in addition to associated products and services, including web hosting, brand management, and domain parking.
.biz is a generic top-level domain (gTLD) in the Domain Name System of the Internet. It is intended for registration of domains to be used by businesses. The name is a phonetic spelling of the first syllable of business.
.club, often stylized as .CLUB and sometimes dot-club, is a top-level domain (TLD). It was proposed in ICANN's new generic top-level domain (gTLD) program, and became available to the general public on May 7, 2014. GoDaddy is the domain name registry for the string.
.one is a top-level domain. It was proposed in ICANN's New generic top-level domain (gTLD) Program, and became available to the general public on May 20, 2015. One Registry and ARI Registry Services are the registries for the domain.