Karminator is a place where you can track your daily karma - the achievements and failures of your day to day life.
Each incident in your life is either an achievement (a positive karma) or a failure (a negative karma). You can keep a track of all your karmas and get an indication of where your life is heading.

Why keep a log of your daily achievements? Because going through it at a later point can boost your positive energy tremendously. Prominent blogs like LifeHacker and Slacker Manager have repeatedly promoted the use of a Yay-me! file. It's a file where you keep record of all the great work you have done. From the original SlackerManager article (it seems to have gone offline):

The basic idea is simple: you just keep a file of good stuff you do. When you figure out some trick new process that saves hours per week, you make a note about (don't forget to datestamp it) and drop it in the yay-me file. When you finish a project on time and under budget, you make a note that points to supplementary project files and you drop it in the yay-me file. Since it's only your eyes on the yay-me file, you can feel free to drop in even the most trivial bits good cheer. Did you cover Eleanor's phone while she went to lunch? Goes right in the yay-me file.

The reason for the yay-me file is two-fold. First, when you feel like you need to patch your personal suck you can crack open the yay-me file for a blast of good vibes from the past. The yay-me file reminds you that you aren't always lame and that you make good decisions and you do good work. And gosh darnit, people like you!

The second reason for keeping a yay-me file is a bit more pragmatic. Each year, you haul that thing out and you grab the cream of the crop. You clean it up a bit and, depending upon your degree of boldness, you either staple the good stuff to your annual self-evaluation, or you send it separately to your boss for their perusal while they're trying to remember who you are and what you do, or you just bring it along as ammo to the actual performance evaluation meeting. Or all three. The idea here is just to help other people remember how great you are.

Now, why do you have to track your failures? Because it helps in preventing you from doing the same mistake again. Obviously, identifying a mistake is the first step in correcting it.

You can make your karma public or private. If made public, others can see, comment and vote on your karma. Karmas with most number of votes and comments float to the top of the list and ultimately into the front page in a digg like fashion. You can very well make your karma private in which case only you will be able to see it.