Nielson had their partial program open a short time ago, but it was restricted to those with land lines, which many people are doing away with entirely.  This full version works with cell phones, I guess.  If you are accepted, they send you a hand scanner which you use to scan the bar codes on all items you buy/bring into your home for personal use (not for resale, you stockpilers, you) and then once a week you dial an 800 number and hit send.  That’s it.  My scanner beeps all the time in protest over the quantities I purchase.  Enter quantity:  440.  BEEP!:  are you sure?  hehehehehe

Again, I’m all about easy, so if it takes too much time or requires too much hoop-jumping, it’s not for me.  Try Nielson and see if 1) you are accepted and 2) it’s something you enjoy doing.  They give you all sorts of clap-trap about how your influencing manufacturers, but I’m only doing it for the money (points).