From ShoeMoney.com:

As most of you know a few months back my site was hacked. What many people dont know is that was actually the first of 2 times the box was hacked. […] Well after going through the logs greping for the ip range that hacked my box I found that the person found my site from Google! Specifically using Google code search. Now while this was interesting it still did not explain how the page was even indexed…. ohh wait I use Google Sitemaps and I had it on to index everything (the default setting) OUPS!! […]

Read the article, then read some comments. Basically, let this serve as a reminder that when you slack off as a webmaster, you (and your clients) will suffer. I do believe this is what the author is trying to do, remind you to not be stupid when it comes to your web servers. For most of us, he is not giving us any new information and I think he knows that. He did, however, remind this webmaster to take some time and look for exploits on all of his client’s sites over the next couple of days.