They are. Our company use them on a weekly bases if not daily. New prospects are added; when they become customers our database is adjusted accordingly and so is our little software program we use to send out email newsletters etc. Handy, time and 'paper' saving tool, databases are.
Every company should use one (or two) to keep in touch with their prospects in order to turn them into a customer. And of course to keep in touch with your customers (happy reminders ring a bell?)
Then why does one of my suppliers keep sending me 'newsletter' emails filled with offers we can benefit from once we become a customer?
We are a customer!