The success of an Internet marketing campaign can be measured by its conversion rate. Conversion rates may be based on getting readers to subscribe, bringing customers over from another site using an ad, or getting people to buy something.
Online marketing is direct response marketing, so you need to encourage the customer to act. And action is determined by letting customers know what and why they should click. They need a compelling differentiated benefit and a call to action.
Tell them what to do — and why — and they just may do it.