The domain's purpose is to act as a single point of contact for individuals and businesses, providing a 'live', global contacts directory service by housing all types of contact information directly in the Domain Name System, without the need to build, host or manage a traditional website. Additionally, as of July 2010, every .tel acts as an OpenID and an increasing number of VoIP clients, including Kiax, Phoner Lite, VoipGATE and others enable the 'dialling' of a .tel domain directly from their soft phones. .tel also natively supports the hCard micro-format.

Telnic started publicly accepting applications for name registrations on February 3, 2009 after a closed Sunrise period for trademark holders. At present, information in tel can be controlled by the owner through a website control panel that Telnic has created for registrars to provide to their customers, or through free clients for BlackBerry, Microsoft Outlook iPhone, Android and some third party VoIP softphone clients, including voipGATE. With the introduction of support for OAuth in July 2010 however, new third-party clients and services can be available to .tel owners to publish to their domains securely was made possible, including the possibility of editing .tel information offline via SMS gateways (see http://twitter.com/2tel for a proof of concept). The control panel is an open source application, and can be changed or completely replaced by registrars, as the application programming interfaces required to manage tel information in the DNS were released by Telnic in October 2008.

When viewed over the Web, all .tel domains point directly to a Telnic proxy webpage that is populated 'on the fly' presenting the respective domain name owner's contact data stored within the DNS system (currently hosted by Telnic but which will be opened to Registrars once accreditation procedures are formalized). tel domains can also be accessed without opening a browser on many devices through open source applications or through direct DNS lookups.

In contrast to other top-level domains .tel information is stored directly within the Domain Name System (DNS), within the actual domain name record, as opposed to the DNS simply returning details (such as IP addresses) of the machines on which information can be found.

Information regarding possible exploitation or abuse by spammers and malware is not yet available due to the lack of verifiable data. But as Telnic has enabled the DNS records to be encrypted using 1024-bit encryption and stored in sub-folders which are hidden until paired with a public private key handshake with individuals, there is some protection from spammers.

The full extent of the effect the extra data will have on the DNS system is unknown.

This TLD was released to trademark holders only until February 3, 2009, perhaps suggest that the resulting database of contact information can somehow be trusted as the "official" contact information of the "rightful owner" of those trademarks. However, after the short period of registrations restricted to trademark holders only (the "Sunrise" period), anyone willing to pay a premium price was allowed to buy any domain name (the "Landrush" period) regardless of who owned the trademark.

Furthermore, now in "General Availability", anyone is able to register any name (assuming that it is available for registration) without paying a premium price.

The information held under the .tel domain will be no more accurate or trustworthy than any other user defined data held in the DNS system. It will be down to individual .tel owners to choose what they wish to store there.

As with all other gTLDs, trademark owners can utilize the Uniform Domain-Name Dispute-Resolution Policy (UDRP) to claim trademarked domains back.