I know some people that generate huge incomes by buying and selling domains. Sometimes they buy never-used domains and wait until receive a good call to sell them; nowadays, when almost all nice domains are taken, they are working a bit different: They create some records of domains that are about to expire, their Google Page Rank, their Alexa traffic and some other statistics and, when the domains expires, the quickly buy them.

There’s a paid search engine that helps with this work. Dots.org is an expiring domains search engine. You can search using many filters including the expiration date, the domain type, the part of a domain and many more. You can also have access to different language dictionaries in order to get some help in your searches.

If you want to use this search engine, you have to be a member. There a many options for this. You can become a one day member or buy a 1, 6 or 12 months membership.

By the way, below is a chart taken form this site that explains us the domain expire process.