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.
If you're wondering what a sales funnel is, simply imagine a real-world funnel. At the top of that funnel, some substance is poured in, which filters down towards one finite destination. In sales, something similar occurs. At the top, lots of visitors arrive who may enter your funnel. However, unlike the real-world funnel, not all who enter the sales funnel will reemerge out from the other end.