The business of resale of previously registered domain names is known as the "domain aftermarket".
Various factors influence the perceived value or market value of a domain name. They includ:
1) the natural or "organic" traffic that can be attributed to web surfers typing in a domain name in their web browser as opposed to doing a search for the site through a search engine.
2) Branding Opportunity. The ability to have a term recognized and easily recalled as a brand for a company or entity.
3) Re-sale value. The ability to spot trends and predict the value of a name based on its length (short is preferred), clarity, and commercial use. The word loan is far more valuable than the word sunshine.
Generic domain names have sprung up in the last decade. Certain domains, especially those related to business, gambling, pornography, and other commercially lucrative fields of digital world trade have become very much in demand to corporations and entrepreneurs due to their importance in attracting clients.
The most expensive public sale of an Internet domain name to date, according to DNJournal, is porn.com which was sold in 2007 for $9.5 million cash.
Business.com $8 million
Bought by the Californian-based eCompanies. They plan to develop the site as a business-to-business service.
AsSeenOnTv.com $5.1 million
Bought for an extortionate sum and now the place to buy all your As Seen On TV products.
Altavista.com $3.3 million
Bought by Compaq for its search engine Altavista. It means you no longer had to type in the cumbersome URL ww.digital.com/altavista.
Wine.com $2.9 million
Not only did VirtualVineyard.com acquire the domain name wine.com back in September 1999 but it also bought a live site. However it's the URL that VirtualVineyards really wanted, the VirtualVineyard's content was immediately swapped over to the Wine.com domain.
Autos.com $2.2 million
The sale of this domain was conducted by Hit Domains. The URL was bought by CarsDirect.com, the number one car buying site on the web. Autos.com is now the front door for the company's various auto services.
Express.com $1.8 million
Now home to the online audio and video retailer DVD Express.
Wallstreet.com $1m
This domain was sold in April 1999 by Ehud Gavron, who runs an ISP business in Arizona. Online casino Players Sportsbooks and Casino bought Wallstreet.com and they run a stockmarket gambling service on the site. Players Sportsbooks and Casino are based on a tiny island in Venezuela - presumably for tax reasons.
Rock.com $1m
Yes, you've guessed it, this site is now devoted to all matters rock music related.
Websites.com $970,000
This desirable domain was auctioned off by Great Domains and now is home to Verio, a company that provides Internet and web hosting services to businesses.
Drugs.com $830,000
Drugs.com was bought from Eric MacIver in May 1999. MacIver had originally planned to set up a pharmaceutical distribution site at Drugs.com. Internet start-up incubator Venture Frogs bought the domain and is now running a drugs and pharmacy portal from there.
Although the current domain market is nowhere as strong as it was during the dot-com heyday, it remains strong and is currently experiencing solid growth again. Annually tens of millions of dollars change hands in connection with the resale of domains. Large numbers of registered domain names lapse and are deleted each year. On average, more than 25,000 domain names drop (are deleted) every day.
A webmaster creating a new web site either buys the domain name directly from a domain name registrar, or indirectly from a domain name registrar through a domainer. People who buy and sell domain names are known as domainers. People who sell value estimation services are known as appraisers.