Using Testimonials In RE Marketing?

Have any of you used testimonials from former sellers that you bought from in the past for marketing purposes?

The reason I ask is because I’m currently reading “Influence: The Psychology of Persuasion” by Robert Cialdini which is about using influence in marketing. He says that people are more likely to do something that they think other similar people or people in a similar situation as theirs did. So, I thought about using testimonials from people I bought from in the past that were pre-foreclosures, probates, fixer uppers, etc and putting the testimonials on my postcards to people that are in the same situation now.

What do you think?

Dan Kennedy says to use the testimonials, too.