Absolutely none. It's too easy for someone to say "no thanks". If anything, I'll go in person and deliver info on my boards. At least, it gets me to "I'll think about it".
Try to locate a marketing agency in your area. This would be a 3rd party that handles marketing for business owners who don't have time or the experience to market their company. I own 4 bb faces and all are taken by agencies. I offer competitive rates in exchange for 1 year agreements. I do this part-time and it allowed me to eliminated a lot of time and effort I did to market my boards.