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/20101206224738/http://www.searchengineoptimising.com/glossary/glossary-of-computer-and-internet-terms/ppl
PPL (Pay Per Lead) is a form of payment structure whereas the publisher gets paid by the advertiser based on how many leads are created by an advertisement.