In the business of marketing domain names, "premium" domain names are often valuable, and have particular characteristics that are used in the domain appraisal process. For example, the names are short, memorable, may contain words that are regularly searched on search engines, and/or keywords that help the domain name gain a higher ranking on search engines. They may contain generic words, so the domain has more than one meaning.

Very short .com domains are valuable as their number is limited. Among the 26 single-letter second-level domains, few are registered because the Internet Assigned Numbers Authorityreserved them in 1993. Those that were already registered were not recalled.