Customer relationship management

How important is customer relationship management? WWF Malaysia has been doing that since I joined. World Vision Malaysia has started to do that as I can see. Even charity body is doing that, needless to say commercial business. If you are a business owner, give it some thoughts. Keep a record  of your customer's birthday and send them greeting email/sms on that day or in prior. Do the same during festive seasons as well. I heard there is software program in the market which can ease the job, although I am not sure about the price.