A value swap is what occurs when a visitor to your website gives you their information for something they consider valuable. It's not a monetary transaction but can lay that foundation. An example of a value swap would be giving visitors a white paper or some valuable information after they fill out a form with their contact information.
It's a fine line to walk between giving site visitors enough information to convince them of your expertise while not giving away the farm. A value swap can help create some balance. On our site we have an SEO Score Card that we give away for free in exchange for visitors taking the time to tell us about their website, search keywords they want to target and some other information. These score cards take about an hour to make but they also serve as a valuable sales tool for us. After delivering the score card we are in an excellent position to recommend Small Box services to fix any problems the score card revealed.
Our client Antique Helper gives free antique appraisals in exchange for contact information and this creates auction consignments. Someone wanting to know what their antique Tiffany vase is worth might also be interested in selling it via auction when they find out it's worth $3000!
Does your website have a value swap? Why not? I would guess every business has some piece of information they can swap. Figure out what that is and start swapping!