The surveys are interesting and not too long, the products are usually from reputable national brands, and I often get samples to try sent right to my home, along with compensation for taking the surveys ($3 each, paid by paypal).
I received this from them:
PineCone Research is growing and we invite you to help! We are offering select members the opportunity to recommend membership to a friend or relative who is NOT a member of their household.
Do you know of households that would like to join the PineCone Research Panel? If so, please FORWARD A COPY of this email to each household you would like to refer so that they may click on the registration link shown below. That household should complete the registration form themselves and submit it. REMEMBER THAT ONLY ONE PERSON PER HOUSEHOLD MAY REGISTER. Multiple registrations of the same Household will void all registrations.
Here is the link to the registration:
Check it out if you are interested