lol, if you use these shops anyway and don;t mind having what you buy stored in a database, then why not, you get money back for doing what you do anyway
Pasta - they won't record what you buy though. Just how much you've spent, where, and when. Unlike loyalty cards which will record everything you've actually purchased.
It's mostly the equivalent of 1% cashback on what you spend. Nectar has the advantage that you can spend (almost) as you go - when you have £2.50 accumulated it can come off your next grocery bill - rather than waiting for mailings every few months a la Tesco. You can also save them for larger amounts and special offers.
You get occasional mailings with money off/extra points coupons - an attempt at least is made to match these to things you buy. Not always successful though....
Cons - another card to carry/intenet password to remember (if you register online). And Big Brother if you are clinically paranoid
They must do as I received vouchers in the post from both Sainsburys and Tesco specifically for products - or products in the same range - that I've purchased in the past.
I go to Tesco and get tesco points with Eon as well so had a lot of points which converted to rewards. Have had loads of days out in London with them and bought lovely jewellery at Goldsmiths as well. They usually convert to three or four times the value unless you use them for food, so not worth using them for food.
OH and I have one and both collect points of fuel food and stuff i buy on line -i started in April 12 and at Xmas had £140 worth of points on the card which basically bought all the extra goodies for Xmas -we would have bought all the groceries fuel etc anyway so that was £140 for nothing really so I'm well pleased. I get vouchers in the mail which are pertinent to what I buy regularly so I'm not bothered that they make a record of my purchase - its no big deal.
You can also register for Nectar Ads. You watch adverts on PC, IPad etc and earn points, up to 250 per week. If you've got time to watch the ads that is and you have to watch them to get your points because a banner comes up asking if you're still watching and you have to click on it within 5 seconds.