The hierarchy of domains descends from the right to the left label in the name; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example: the label example specifies a node example.com as a subdomain of the com domain, and www is a label to create www.example.com, a subdomain of example.com. Each label may contain from 1 to 63 octets. The empty label is reserved for the root node and when fully qualified is expressed as the empty label terminated by a dot. The full domain name may not exceed a total length of 253 ASCII characters in its textual representation. Thus, when using a single character per label, the limit is 127 levels: 127 characters plus 126 dots have a total length of 253. In practice, some domain registries may have shorter limits.
If you’re still with me then you might be wondering who came up with all of this. The answer is ICANN — the Internet Corporation for Assigned Names and Numbers. ICANN is a non-profit whose role is to coordinate all the names and numbers that keep the Internet online. They outsource a lot of the heavy domain name lifting to registries like Verisign, who pay ICANN for the privilege.
When you type google.com into your browser, the domain is split into parts by the “dot”, from right to left. The first part is “com”, so your computer checks the root zone file to see which registry manages the .com TLD. It then checks with this registry to see where the next part, “google”, points to. The registry returns the IP address 18.104.22.168, and your computer can then ask Google to send their homepage over.
As I noted above, ccTLD fans had a lot to be happy about over the past couple of weeks with a terrific run of sales led by that $255,200 Casino.ro jackpot at Sedo. You saw the six biggest sales in this category on the all extension chart at the top of this report, so the highest sale from this group that you haven 't seen yet is the #7 name on our latest weekly Country Code Top 20 Sales Chart. That is Sedo's $7,854 sale of Major.co.
Sedo went on to sweep the first eight chart entries and 17 of 20 places overall, including another six-figure home run with #2 Jobster.com at $200,000. Their haul also included the other two ccTLDs in the first five - #3 GolfTV.co.kr at $69,600 and #4 (tie) GolfTV.kr at $58,000. Bobet.com shared that #4 spot with GolfTV.kr by attracting $58,000 as well.
For the most part, you can pick whichever TLD you prefer, though a few have restrictions -- you can't buy a .edu domain unless you run an accredited post-secondary school. Many, but not all, country-specific domains (.us, .uk, .jp) are restricted to citizens of the country in question. Unrestricted country domains are often used for "domain hacks," where the extension becomes part of the title, such as YouTube's alternate address, "youtu.be."