There is no defined date range for data contained with a drop list, as they can contain anywhere between 1 day's worth of expiring domain names, to 30 or more days worth.
Other drop lists provide more detailed statistics, including, among others, PageRank, Link popularity and Alexa rank.
Critics say that promotion and marketing of so-called droplists may encourage cybercrime and payoffs at registrars, indicating that a registrants can lose their domains without abandon.
When a domain name is abandoned, or the period of validity is not renewed (expires), the webhost and registrar then action a "deletion" (the drop).
[1] Sometimes, people get locked out of their email and cannot reply to the renew request (or otherwise obstructed or hacked), and their domainname may be deleted and offered as available.