Google claims their users click (organic) search results more often than ads, essentially rebutting the research cited above. A 2012 Google study found that 81% of ad impressions and 66% of ad clicks happen when there is no associated organic search result on the first page. Research has shown that searchers may have a bias against ads, unless the ads are relevant to the searcher's need or intent 
Good question, for most directories I use they ask for mobile number to send a message of verification, for the ones which phone you for verification inform the company before hand to tell their customer service people to be ready. I know the bigger the company the more tricky these things get you just have to find out what works best to answer the calls even if they give you a direct number to use.
When it is time for your organization to start creating new products or enhancing items already on your product line, organic search can maximize your efficiency and gauge market demand. You will be able to see which products are sparking the most interest through increases or decreases in organic search. You can then take the information from the Data Cube and compare it to trends within your own sites and the performance of your competitors to create a product line that maximizes your investment.