One of my fave stories in the Netsize Guide 2009 is a longer story about how Bird's Eye, the frozen food brand, ran its engagement marketing campaign in the UK with SMS. Alex Meisl the Chairman and co-founder of Sponge Ltd the mobile marketing agency, is interviewed in the Guide and explains.
They used SMS because that works for everyone, on every phone. They printed a unique code to each package of the foods and gave a chance to win cash prizes every day via SMS participation. A monthly grand prize would pay off their mortgage in full (nice prize in these economically troubled times..)
Bird's Eye would send product info to buyers, as they knew from the unique code, what product had been bought. They sent nutritional info and also cooking recipe guides.
Then they would offer suggestions of related Bird's Eye products and promotions, such as "You've bought cod fishcakes, why don't you try our ew potato waffles with that?"
They achieved over 100,000 opt-in customers who wanted to hear more from Birds Eye via the phone! Great little simple campaign.