Not a diary, but...
As a sysadmin, one of my responsibilities is to ensure nothing offensive goes through our Internet connection. We just rely on manual monitoring now, and a list of blocked sites, but I used to go through the Internet caches of each browser. Some of the stuff I found..

One that sticks in my mind is a video of a young lady in leather walking up and down on a man, while she was wearing 5inch heels. What made me wince a little was the she stopped at his groin, sorted out his balls, then stepped on them.

Oh, and one user had an interesting collection of sites: He went to loads of sites featuring nude pregnant women (sort of understandable), guns (erm ,dangerous territory here) and Hitler worship (rather worryingly, he did apparently think Hitler was a God and Goebbels was some sort of Angel).

Oh, and another user had a thing for ( apparently legal) boys with big dicks. Wonder if his boyfriend ever found out.

Most of the rest of the porn I used to find was a mix ranging from softcore (nude women and men), through hardcore through to bestiality and, let's say an unusual use for bodly secretions.

As for the most embarassing time? Well, I did once see a user (not mentioned above) typing out an email in which he came out to his best friend and admitted he fancied him.
(Ok, I'll get me coat, Tue 6 Feb 2007, 9:37, Reply)