Domain facts:

It is very important to remember that a domain (name, address) must be valued separately from the website (content, revenue) that it is used for. The high prices have usually been paid for the revenue that was generated from the website at the domain's address (url.). The intrinsic value of a domain is the registration fee. There is no such a thing as a current market value for a domain: It just takes what somebody pays. The Fair Market Value of a domain can be anything from the registration fee: The lowest known past selling price, the highest known past selling, price, the most recent selling price, or just any past selling price and any of these (or any sum resp. division etc.) is usually added to the current or expected revenue from the web content (advertising, sales, etc.). Domain (name + ext.) should not be mixed with website (content + revenue). The estimation by appraisers are always the addition of what they would like that a domain is worth together with the effective/expected/desired revenue from the web content. Some people put value on the length of the SLD (name) and other people prefer description capability, but the shorter a SLD is, the less descriptive it can be. Also, if short is crucial, then the TLD (extension) should be short too. It is less realistic to get a domain like LL.travel or LL.mobi than a domain travel.LL or mobi.LL. This illustrates the relativity of domain value estimation. It can be safely put that the revenue af a web (content) can be easily stated, but that the value of a domain (SLD.TLD aka name.ext) is a matter of opinions and preferences. In the end, however, any sale depend of the estimates by the domain seller and the domain buyer.

Overview

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.