Much of this is steeped in buyer psychology. The best marketers in the world know that there is a psychological process that must occur for prospects to whip out those credit cards and turn into buyers or even hyper-active buyers. One such person whose perfected this process is Russell Brunson, an "underground entrepreneur" who founded a company called ClickFunnels, a sales funnel SaaS business that empowers marketers from around the world to build marketing automation without all the hassle.
Have someone examine the ratio of visitors to your page, versus how many people enter their contact information to get access to content. A high percentage means you are targeting your demographic well, and should continue to offer similar content. A low percentage means you need to invest more in adding value to the free content or service you are offering.
In brief, we are inclined to go along with someone’s suggestion if we think that person is a credible expert (authority), if we regard him or her as a trusted friend (liking), if we feel we owe them one (reciprocity), or if doing so will be consistent with our beliefs or prior commitments (consistency). We are also inclined to make choices that we think are popular (consensus [social proof]), and that will net us a scarce commodity (scarcity).
To better understand the concept of a sales funnel and just how you can implement it in your own business, let's look at the following image from Shutterstock. On the left side of the image, you see a magnet. That magnet is attracting customers, which happens a number of ways. From blogging to social media to paid ads and everything in between, how the visitors arrive to your website has some impact on the success of your funnel.
As a software engineer myself, I can tell you that building funnels from an application standpoint takes massive amounts of work. There's a great deal of coding and integration that's required here. From email systems to landing page implementations to credit card processing APIs, and everything in between, so many platforms need to "talk," that it takes the bar too high for the average marketer.