We just started calling past customers to get their emails. We aren't sending our reminder post cards via snail mail anymore and will only be doing email/text reminders if they want them. It is perfect timing to because we are pushing sign ups on fittlebug for them to keep track of referral credits, book their future appointments, etc.
The reason for calling is to inform them of this with a reminder of who we are incase they forgot. Instead of just calling to say, hey! it's time to get your carpet cleaned again, you ready to schedule? That annoys people.