I have personally experienced a fair number of lost mail.
This explains part of what is going on with the webnet.
http://www.cs.washington.edu/homes/ethan/hubble/nsdi08/hubble.html
http://www.networkworld.com/news/2008/041008-internet-black-holes.html
http://www.securityfocus.com/news/282
http://www.defendingthenet.com/NewsLetters/Internetdarknet.htm
http://timesofindia.indiatimes.com/Black_holes_in_the_internet/articleshow/2948238.cms
This explains part of what is going on with the webnet.
http://www.cs.washington.edu/homes/ethan/hubble/nsdi08/hubble.html
http://www.networkworld.com/news/2008/041008-internet-black-holes.html
http://www.securityfocus.com/news/282
http://www.defendingthenet.com/NewsLetters/Internetdarknet.htm
http://timesofindia.indiatimes.com/Black_holes_in_the_internet/articleshow/2948238.cms