I know that like the rep points, anyone can give you whatever points they want, negative or positive, but I find it strange that someone decided to down vote a post that is 1 year old without a single explanation.
At least with the reputation system you get to describe the reasons for your selection.

I'm not crazy about this anonymous up/down stuff. I'm a big believer that if you criticize or praise someone in a public way, you should attach your name to it so everyone knows who did it.

I have one from a year and a half ago where someone must have weighed in very recently since up/down has only been available for a month.

http://www.daniweb.com/forums/thread116831.html