From the FAQ:
If you decide to cancel your account, here's how:
1. Click the "Contact Us" link at the bottom of any CafeMom page.
2. Under "Self-Service", click the link that says "Cancel my CafeMom Account".
3. Let us know why you're leaving (optional).
4. Click the "Submit" button.
We will process your request and you will receive a cancellation confirmation once your account has been canceled.
Sorry to see you go! =) This is such an addictive site!
at 11:58 AM on Jun. 10, 2011