How do I do referrals?

If you click on "Home" in the navigation, and then "Edit Profile", there is a referral link on that page (before you get to "Manage Dividers"). You can give someone that url and they will be directed to the HP registration page, with you as the referrer.

If you can't give them the url, you can just give them your account number and ask them to put it in the "Referral ID" box when they join.

Here's a little more about referrals from the help pages

I hope this helps!

What Sass said! :P