Why does itunes not pop up when I plug in my ipod touch?

You have not set it up to be this way. Here is how to fix this problem:

1. Plug in your iPod Touch.
2. Open iTunes manually.
3. Wait for iTunes to figure out that there is an iPod Touch connected to the computer.
4. Click on the iPod Touch menu in the navigation bar to the left of your iTunes window.
5. A screen should pop up with an iPod Touch picture and a bunch of tabs at the top of the screen.
6. Towards the bottom of the screen, there are check mark boxes. Check the one that says 'Automatically open iTunes when iPod is connected'.
7. Eject the iPod after clicking out of the iPod Touch menu, and it should work now.