The Internet Archive discovers and captures web pages through many different web crawls.
At any given time several distinct crawls are running, some for months, and some every day or longer.
View the web archive through the Wayback Machine.
Web wide crawl with initial seedlist and crawler configuration from October 2010
TIMESTAMPS
The Wayback Machine - https://web.archive.org/web/20110106204423/http://www.searchengineoptimising.com/glossary/glossary-of-computer-and-internet-terms/popunder
A Popunder is very much like a popup only instead of popping up on your screen it will open up a browser that is underneath your open windows. As a result you may not notice it for several hours.