- Email them at least every other month. Maybe do an ex employee eNewsletter.
- Do an exit interview. Find out why they are leaving, if they would be interested in returning at some point, and let them know you appreciate them continuing to talk about the good aspects of the organization.
- If appropriate, offer a commission on any sales they bring your way, including their new employer.
- Build a online staff and alumni community. This could be a good way to find about something that was done before an employee left.
- Outsource additional weekend work to ex employees, if they are interested.
Employees that leave your organization can be a great resource, and if they are leaving on good terms, had a positive experience and are kept up to date and excited about your company, even ex employees can be a great source of Buzz.