|TLD type||Country code top-level domain|
|Registry||NIC.IO (run by Internet Computer Bureau)|
|Sponsor||IO Top Level Domain Registry (Cable and Wireless)|
|Intended use||Entities connected with British Indian Ocean Territory|
|Actual use||Popular with startup companies; little of anything related to the territory itself.|
|Registration restrictions||None for 2nd level registrations; 3rd level registrant must be resident of British Indian Ocean Territory|
|Structure||Registrations are taken directly at the second level or at third level beneath various 2nd-level labels|
|Documents||Terms & Conditions; Rules|
|Dispute policies||Dispute Resolution Policy|
Other than the Diego Garcia atoll, the territory has been uninhabited since the existing population was expelled in 1973 and has no government of its own. Google currently treats .io as a generic top-level domain (gTLD) because "users and webmasters frequently see [the domain] more generic than country-targeted".
The .io domain extension has existed since 1997, and has grown steadily in popularity ever since. .io domains now compose 0.1% of all websites.
The first IO-related domain to be registered was the domain data-io.com, which when it was registered in late 1986 was the 45th domain name ever to be registered.
The first .io-domain was not registered until 1998, when Yahoo Inc registered the domain yahoo.io.
The following table lists some of the first .io-domains to be registered:
Labels for .io domains may only contain alphanumeric characters and hyphens and must be between 3 and 63 characters long. Domain names can not begin with, or end with, a hyphen symbol, and may not contain two consecutive hyphens. The entire domain name may not contain more than 253 characters.
The right to administer domain names is given to approved organisations by the IANA. The Internet Computer Bureau administers .io domains. The Internet Computer Bureau is a British company that, in addition to the right to sell .io-domains, also holds the right to sell .sh-domains and .ac-domains, the top-level domains for Saint Helena and the South Atlantic islands of Ascension.
Registration and Restrictions
Both individuals and organisations are allowed to register .io-domains.
In order to register .io domains you must not be registered or established in the British Indian Ocean territory. In order to register third-level domains such as xyz.com.io you have to be an inhabitant of the area. Any second-level domains used by NIC.IO and top-level domains can not be used as a third-level domain. For example the domain "com.com.io", "org.com.io" and "biz.com.io" are all restricted.
.io domains may not be used "for any purpose that is sexual or pornographic or that is against the statutory laws of any Nation". Breaching this requirement "NIC.IO reserves the right to immediately deactivate the offending registration".
.io domains may be registered for a minimum of one year, and a maximum of 10 years.
To many[weasel words] the .io-domain is used with little thought of its origin.
"Nowadays, a lot of TLDs are used without any relation to the original country, such as .ly, .io, .me."—Jens Segers - Founder of Auki.io, 
"We took it because it refers to ‘input-output’. And our customers (mostly tech savvy people) understand it like so."—Ben Verbeken - Seats.io CEO, 
IO also stands as an abbreviation for Internet Organization. In addition, .io domains are often used for open source projects, APIs (such as put.io API and pen.io API) and online services.
Investing and Reselling
As with most domains, many .io domains are bought by third parties who do not intend to use them for websites. There is no exact figure of how many of the .io-domains that have been bought that are actually in use, but there have been multiple cases in which .io-domains have been sold for substantial amounts of money.
This table lists some .io-domains that have recently successfully been sold:
|Selling Price||Domain Name|
One of the main reasons behind this popularity is the availability of .io domains: Though it is often hard to find a fitting .com domain, there are plenty of corresponding .io domains available that have not yet been registered. This may be due in part to registrations being suppressed by the relatively high price of .io domain names.
218 out of the one million most popular websites use an .io–domain. These are the most popular domains using the .io domain extension:
|Rank||Global Rank||Domain name|
- IDN Code Points Policy for the .IO Top Level Domain, NIC.IO
- "IANA -.io Domain Delegation Data", Internet Assigned Numbers Authority, 28 March 2014
- "Geotargetable domains". Google. Retrieved 6 May 2013.
- "Historical trends in the usage of top level domains for websites". Retrieved 2014-10-16.
- "The Oldest .io domains". Retrieved 2014-10-29.
- "NIC.IO - The Indian Ocean .IO Domain Registry and Network Information Centre - Whois Search". Retrieved 2014-12-29.
- ".IO Domain". Retrieved 2014-10-29.
- "Eigenschaften einer .io-Domain" (in German). United-Domains.
- RFC 1035, Domain names--Implementation and specification, P. Mockapetris (Nov 1987)
- "Internet Computer Bureau".
- "RULES for the .IO Domain and Sub-Domains".
- "Register dot IO (British Indian Ocean Territory) domain names".
- ".IO Domain at Gandi Rates".
- "WHY .IO?".
- "Popularity with startups".
- "Top Websites with .io".
- Beattie, Russell (2013-02-12). "The rise of .io domains for well crafted web services". Retrieved 2014-04-24.
There's lots of open source projects (Redis, Brackets, Launcher), a few mobile-app landing pages (Avocado, X-Ray), a ton of new web apps and services, several conference pages (Lightning, Renaissance, Resonate) and a few older companies or organizations who've changed their name to take advantage of a cleaner .io name.
- "Flippa". Retrieved 2014-10-29.
|This Internet domain name article is a stub. You can help Wikipedia by expanding it.|
|This British Indian Ocean Territory-related article is a stub. You can help Wikipedia by expanding it.|