Just days after Verisign launched the Site Finder Service, ICANN wrote a strongly worded letter ordering them to disable it. Verisign complied, but not without writing a strongly worded letter of their own, in the form of a lawsuit. Verisign argued that ICANN overstepped their bounds in trying to control their activities, and ICANN argued… that Verisign overstepped their bounds in performing those activities.
Many registrars reserve the right to revoke your domain name for specific reasons, typically if you use the domain for illegal purposes or purposes deemed unacceptable (such as spamming). Many contracts contain a clause letting the registrar delete your domain name for no apparent reason. The implication, of course, is that the domain name is the registrar's, not yours.
Domain names can be used in a number of ways. Direct visitors to your website’s home page or use complementary domains to send them to specific areas of your website ( e.g. yourcompany.jobs for a careers page). Or, forward a custom domain to an existing social media account, like your Twitter profile or Periscope channel. With a domain name you can even set up custom email addresses like email@example.com, which can be used to conduct business or communicate with your followers. More.