Take a risk?
Most marketers will do just about anything to persuade people that buying their product is risk free. Hey, we even use terms like "risk free!" and "money back guarantee if not satisfied". Business to business sellers often rank risk as the #1 reason organizations don't end up buying from them.
Word of mouth is directly proportional to risk. If I take a risk and it works out, I tell everyone. If there was no risk, it's not interesting (remarkable) and that's the end of that.
"You took quite a risk trying our service/believing in our product/sticking with us and we appreciate it."
Brand pioneers and early adopters are proud of their stance. It makes us feel good to share war stories. Be proud of your risk takers and they'll return the favor. Create products that are riskier to adopt and if you can get over the hump, you'll be rewarded with buzz.