Thanks for the reply !

You're right about customer service, I guess it's something that is so integral (and essential) to what I do that I tend to forget it's also a marketing tool. I just think of it as something I do, because small businesses do customer service and large ones tend not to !

GiffGaff is something I hadn't come across before. I can see it working really well for some businesses, is it still effective for businesses in a niche where queries need accurate technical answers ? I look forward to seeing your Hive version - maybe co-ordinate with Reverio (which is like a Hive Quora) to feed Q&A back and forth.

Letter writing and phone calls are a good one. I tend to think of them as maintenance for existing customers rather than a way to get new business, because I'm a great believer in getting informed consent before contacting people.