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.
Using tools like Google+, Hangouts, and Skype to hold online discussions or webinars is the best way to personalize with your customers. These are better techniques to use when it comes to generating the best sales leads because the visitors are left with a personal, trustworthy experience. Conducting such webinars over the phone or using Hangouts to share screen engages the customers and creates interest in what you have to say. Having a question and answer session, in the end, can help clear all the doubts your customers might have and even help you identify the common issues which you can then work on.
Sales leads are generated on the basis of demographic criteria such as FICO score (United States), income, age, household income, psychographic, etc. These leads are resold to multiple advertisers. Sales leads are typically followed up through phone calls by the sales force. Sales leads are commonly found in the mortgage, insurance and finance industries.