Space NK launched their N.dulge loyalty card relatively recently so during a recent present shop (you know: two presents for her, one present for me etc.) I couldn't resist the flawlessly made up Space NK customer service representative dressed in black when she proffered the glossy leaflet.
Similar to the Boots Advantage card, you get a point for every £1 you spend (online and in stores), and for every £100 spent you get a £5 voucher. There are lots of other benefits which are articulated here.
Despite the silly name, it's probably worth it if you're like me and often find yourself in there when you're craving a 'lotions and potions' hit.