Grass Roots Marketing

Do you have specific strategies for grass roots marketing (leveraging word of mouth, "flipping the funnel," etc.)?  Have you learned any important lessons from recent successes or failures in this area?  I'm looking for a marketer with some experience in this area who might be interested in a bit of mentoring.  If you have a bit of wisdom to share and would like to help, please send me an email at ksheehan@tessituranetwork.com.  Thanks!