Name servers. Most registrars provide two or more name servers as part of the registration service. However, a registrant may specify its own authoritative name servers to host a domain's resource records. The registrar's policies govern the number of servers and the type of server information required. Some providers require a hostname and the corresponding IP address or just the hostname, which must be resolvable either in the new domain, or exist elsewhere. Based on traditional requirements (RFC 1034), typically a minimum of two servers is required.
Absolutely. Owning 'yourname.com' (as well as related domains such as yourname.tech or yourname.me) is a great way to brand yourself and retain control over your name's online presence. With a personal domain name, you can set up a portfolio, blog, or hobby site that’s associated with your own personal life. You can also set up a custom email address like email@example.com allowing your visitors an easy and memorable way to reach you. So even if you have no immediate use for yourname.com, it's wise to register a personal domain to ensure that you (and not some stranger) control your name online.
There is also what is called a ccTLD, or country code top-level domain. These are designed to signify sites located in or associated with certain countries or territories. Most of the ccTLDs actually don't have restrictions regarding who can register domain names. In fact, many ccTLDs are commonly misinterpreted as TLDs. For example, while .tv is commonly registered by television and media related websites, .tv is actually the ccTLD designated for the country Tuvalu. Domain hacks are also a popular use of both TLDs and ccTLDs. This involves creating a full word or phrase when combining the domain name with the TLD to create something your audience will easily remember. A popular example is using the .me ccTLD for Montenegro and combining it with "aweso" to create the domain aweso.me.