Don't stop paying attention. Don't stop being kind. Don't gain 50 pounds. Don't stop flirting. Stay passionate, stay sexy, stay caring. Answer their calls. Unfortunately, too many companies are all candle-lit dinners, fine wine, and "let's talk about you" until the deal is sealed. Once they have you (i.e. you became a paying customer), you realize you got a bait-and-switch relationship.
Put that together with Doc Searls' latest thoughts on relationships, and I'm led inevitably towards my thesis - advertising for new customers is not as effective (depending on product, geography yadayada) as it was, but the simple key proposition to is to manage and delight the current customers. However, the current tools that we've got for companies to manage them are pretty minimal. In particular those tools that allow customers to interact with brands using their mobile. This is an area that I'm thinking about quite a lot, so would be interested to hear about solutions already out there aimed at improving the lot of the embattled current customer.