Be extremely cautious while communicating with the owner. Even if you casually agree to buy the domain via email, the communication might be used against you in court as a legally-binding contract should you change your mind. Until you’re absolutely certain that you want to make a deal, agree to buy the domain provided that all the terms are agreeable. This will leave you an escape hatch if things go south.
When you build a website, you want visitors to come and see what you've done. To get them there, you need a unique domain name that connects to your sites servers. Domain name registration is required to ensure that no one else in the world can claim ownership of your web site's address and to make finding your website simple. Find your one of a kind domain name.