I ordered some - ahem - garments from M&S online yesterday, and today received in my e mail inbox an offer to 'win an M&S voucher for £500'. There was something not quite right about the title, and it wasn't even from M&S, so I deleted it and emptied the 'trash'. The thing is, how did these folk know I'd ordered from M&S? It can't be a coincidence, as I've had this happen before when ordering things online. (Tesco clothes for example) It's always 'an opportunity to win a voucher...' etc. Does it mean there's a spy/virus in my laptop watching what I'm buying and from whom?