Are there people on your email list who consistently forward your emails to other people? Here’s an idea to keep them engaged and take advantage of the free word-of-mouth advertising they’re providing:
Send extra emails with exclusive offers just to these influencers, and invite them to pass them along. No need to tell them they were selected because they’re “frequent forwarders” – simply tell them it’s a thank you for past business or their valued relationship with your company.