This is not a primary lead generation tool, but it can be a nice supplemental one. If you come across an excellent product or service, take the time to provide a detailed, legitimate testimonial with photo, and ask that your complete name and URL be used if using the testimonial in marketing methods. First of all, you build good rapport with professionals within the industry and are more likely to get positive testimonials yourself someday.
Secondly, you get the added exposure of an eloquent statement posted on their Website with your photo, title and URL attached to it. If people are interested they just might check you out.
Finally, you will get your face and message out there for overall branding purposes and further establish yourself as an expert in this field, while creating backlinks to your website.
Note: If you want to provide a testimonial to a professional who does not allow comment posts on their website provide them with a written, signed testimonial with a statement at the bottom that says you are giving them the permission to use any portion of this statement in any on or offline marketing pieces.  The gesture will be much appreciated.