TLDs occupy the highest level in the DNS system domain hierarchy. The number of these domains is limited, and the decision to create a new one of these is made by ICANN (Internet Corporation for Assigned Names and Numbers). There are two types of top level domains—common (.com, .org, etc.) and national (.bg, .us, etc.). All remaining domain names are TLD derivatives (subdomains) and are called Second Level Domains.
Further information on domain name selection:
Domain names should not be viewed only in terms of the alphabetic alternative of the manner in which a given IP address is written out. Additionally, the domain name also plays many other important roles—it introduces the subject that has registered the domain, provides further information on their activity, contains the subject’s or organization’s name or part of it, or is used as a commercial object, and more.
Unfortunately, it is getting harder to register the name wanted, as it most probably has already been registered. All common English-language combinations of words and words with two, three, or even four symbols (with TLD .com) have already been registered. There are many organizations for which commercial activity with domain names has become a rather profitable business activity. These organizations manage to accumulate good fortunes by registering desired domain names and reselling them. Sometimes, domain name prices reach hundreds of thousands of dollars, and in single cases, a domain name can exceed several millions. An advantage that Bulgaria has in this case is found in writing in Bulgarian language with Latin letters. In this way, combinations of words that seem absolutely meaningless to English-speaking people, when written with Latin letters, are completely meaningful concepts in Bulgarian (for example: 'znanieto.com' or 'NaturalnaHrana.com', 'HranitelniStoki.com', etc.). To register the same names in English, a person who is willing to possess them will have to pay several tens of thousands of dollars.
Therefore, a person who decided to register one must act very carefully upon domain name registration. One of the most important conditions is that the name has to be easy to remember and typing, euphonic, easy to pronounce, and even shorter, if possible. The principles when choosing a domain are similar to the ones when choosing a trademark. In the dynamically developing Internet world, the role of your site name and vision becomes more important to the perceptions of others. A significant aspect when registering a domain name is to check for similar domain names bearing different extensions (.com, .org, .net, etc.). It is not that important with personal websites, but it is essential when it comes to business. Let us look at the following situation: Your website runs under the 'my-business.com' name. At the same time, your direct competitor runs their website under the 'my-business.net' name, and also registers 'my-business.org', 'my-business.info', 'my-business.biz', etc. Even though .com is the most common TLD (Top Level Domain), there is a high probability that a customer, searching for your website, will end up visiting another one as possessed by your competitors; your organization may encounter disadvantages due to another site. Therefore, companies that care about their positive presentation on the Internet will register several domains with the same name (usually the most common ones, such as .com, .net, and .org) and direct these domains to their main site. In this manner, your site will load irrespective of TLD name entered by the user (for example: www.microsoft.com).