The likely answer is to do with audience biases. A survey conducted by an email marketing provider is almost certainly going to have different results to one conducted by PPC management tool, as their audiences have different skillsets and biases, skewing the results of their sample. As such, we should take the specific ranking of different strategies in these studies with a pinch of salt.
I want to start off with saying great video above and the information is very thorough. I will be following your advice and guidance to get my new business going. I am very new to the Network Marketing industry but have been introduced to a new Tech Company (called VIV) that has a phenomenal, once in a lifetime opportunity to get into their Founders Circle. I would really like your input on what you think, the link to the video that explains the founders circle is shareviv.com.