We know most about human history for times and places where people wrote things down, what they wrote down was kept, and we can still read what they wrote. Paper is pretty fragile really but seemingly digital records are even more fragile.
“In one study published in the journal Science, 13% of Internet references in scholarly articles were inactive after only 27 months.” 1
I have recently become interested in the UK Web Archiving Consortium. This is a publicly funded consortium whose members include the National Archives and the British Library. They archive “important” blogs and websites, not necessarily official ones, take for example the “Not the Alan Milburn” blog:
Sometimes it’s interesting to see what a politician said then compared to what they are saying now or you might want to record the terms and conditions page for an offer that seems to good to be true. If you just want to archive one page as it is now then why not check out http://www.webcitation.org.