While buying up a ton of domains seems like a great way to make some extra money, the real world results show that it is very hard to make that process profitable. As with any industry, you will have those "golden moments" when someone you read about made it into a million dollar a year business, all while sitting in the comfort of his own home. That could be true, but he probably consumed a lot of alcohol and lost a lot of hair doing it.

1) pending delete auctions.  These are domains that were not renewed and are going through a pretty complicated drop process.  You can backorder these names at the auction venues and then each attempts to "catch" the dropping domain.  If one is successful you win the domain at $59 if you're the only one to backorder the name.  If more than one person backordered the domain a 3 day private auction is held.  Once the domain goes through the drop process, the back links have pretty much zero SEO benifit to the new domain owner.
When you backorder the domain it will say how long you have to place your bid in. Let’s say it says 25 days. If the domain is from one of Namejet’s partners then the auction will start in 2-3 days. If this is an expiring domain and Namejet has to catch it there is a chance they won’t catch it in which case it won’t go to auction at Namejet. If they do catch it then 2-3 days before the auction starts.

The domain name industry is quite similar to the real estate industry in a lot of aspects. There are end users, brokers, consultants and domain flippers or “domainers”. Domain flipping works similarly to buying a house, renovating it (or even sometimes just sitting on it) and then selling it again at a higher price point. The gist of it is: you’re purchasing a domain name and betting it’s worth (or will be worth) more than you paid for it. If you’re right, you get a nice paycheck and move on. Those who make a living out of this just rinse, repeat, and scale.