Earlier this year, Facebook opened up custom audience advertising to a small set of power advertisers. This targeting capability enables you to upload a list of email addresses, leads or customers and advertise exclusively to that list of people.
Last week they announced that they would be rolling this out across all advertisers. On top of that, you can now link up your mailchimp account to easily upload a list of names for targeted advertising.
For local businesses, this is a brilliant way to run repeat visit campaigns and message existing customers with promotions. It could also be used to target business leads for catering promotions. Simply upload your email list and create an offer centered around bringing that customer back for a second visit. This could end up being a low cost method of increasing frequency of customer visits for local businesses.