Your Virtual Friend

While i tried searching for the Os tan software (didn't found any), i manage to find a similar software called cyberbuddy. It greet you when you start your window and if you want to make your cyberbuddy more interesting your can try download a software call answerpad.
With this software you can interact with your cyberbuddy. It have an ai where it can learn your speech and give an appropriate response to it. The more you interact with it the more response it can give to you.

The other software that use the same system is Desktopmate but with different character which you can see above. I get the answerpad from this website too.

There are several more software such as Ultra Hal Assistant. If you want to talk to it online you can go here. The are several type of brain which can talk about general or even uncensored topic. Try it.

If you want to make your own screenmate you can download Screen Mate Builder. But i never try this software but you can try it if you want to.