Why is a web page suddenly taken off Google search results?

I noticed once before that this site was taken off Google’s search results immediately after posting a number in hexadecimal format that was apparently a copyrighted work and therefore, a violation of some other country’s law – something about DMCA. I immediately retracted this post and the web site returned to Google search results.

So I ask, what have I done now? Why can’t I google up my own rantings? Anyone got any hints?