Lets look at some settiings, so you could enter a list of websites to crawl for expired domains on, or you can enter a search query say you're looking to form a pbn to boost your money site, that's about horse riding or something you could put horse riding down there and then it'll search, Google for horse riding and then crawl all the domains that Google brings back to you. Then we've got endless crawl and you basically you put in a few seed websites and then it will just crawl endlessly from those websites. So it will take all the domains off those websites. First they'll check whether they're expired or not. If they're not expired, then it'll start crawling them and then it will crawl the ones it finds from them and so on so on and so on. It will just keep going ok.
Of course, this does not happen equally across the board. Some site owners are lazy and barely put in any effort. As you can probably tell, the four situations I outlined above probably will not occur for website owners who are lazy. Now, for website owners who put in the work and the time for their online properties, you can bet that they would get to benefit from the four situations outlined above.
Premium Domain names are domains that are already registered, but are available for sale at a higher price. Sometimes it will be an individual selling the domain, or it could be the domain registry (Like Donuts Inc. or Radix) selling their top quality inventory at a higher price point. These domains can be priced anywhere from a couple extra bucks to millions, depending on the domain name, the level of interest, or the amount of traffic it organically receives.
Referring domains for anchor phrases usually reveals similar information. What you really want to look out for is whether or not the site has been picked up by a spammer in the past. A lot of times these expired domains were dropped, picked up by a website owner who then tried to rank it for keywords like Viagra, Cialis and whatever. You obviously don’t want that kind of domain.

Thousands of domain names expire every day. The reasons are different. Some owners forgot to renew the domains, some just don't want them anymore or they moved on to other projects. For most people these so called Expired Domains don't have any value. They just see a bunch of Domain Names someone else deleted and move on, but for the people who know about SEO or the value of good Backlinks, Expired Domain Names are money just waiting to get picked up from the street. The only problem is to separate the good ones from the bad ones. That is where ExpiredDomains.net comes into play.