1) Select Your Account link (at the very top of the screen).
It will take you to a page full of setting for your account. Look near the bottom for a block called "Account Preferences". Look for the link to your Email Subscriptions:
Make sure it's not selected, and then you won't receive emails you don't want. Trust your Friends to manage this (but feel free to explain it to them if you're worried). I hope this helps. At worst, it's a start. (At best, we can move onto bigger tasks!) Enjoy.