Did you once cite a source and only record the web address where you found the original information, only to find that 3 years later the site no longer exists? Well, weep no longer! Once something is on the internet, it is out there for good. You need to pay a little visit to The Wayback Machine at Archive.org.
This little tool will take you back in time to see, most likely, several versions of the website you once found, and all you need to do is have the web address to find the info you depended on.
A couple of years ago a distant cousin assured me that his information was safe and sound on his own website, so I didn’t bother to record it myself and only referred visitors to my website wanting his information to his website. Now, with his website no longer active, I just used the wayback machine, copied his information, and incorporated it into my own. Problem solved.