Make a website like expireddomains

HI

I need to know how can I make a website like expireddomains . net
How they are maintaining their database?
From where they get that a domain is expiring, expired etc?
Are they crawling from whois?

 

Check out a previous discussion on the same here

 

I'm also very interested on how do they get all of those expired domains. Someone care to share? thanks in advance.

 

Pasting directly from the another discussion about this

1. GoDaddy domain list over FTP
2. SnapNames Pre-release and Pending Delete Lists
3. NameJet Pending Delete lists
4. DynaDot Pending Delete list and auction lists
5. Sedo Pending Delete lists
6. Multiple drop lists for foreign tlds