Closed-ended experimentation. Consumers are exposed to several variations of landing pages, altering elements like headlines, formatting and layout while their behavior is observed in an attempt to remove distractions that will take the lead away from the page, including the primary navigation. At the conclusion of the experiment, an optimal page is selected based on the outcome of the experiment.
I'm not sure how the algorithm works (or if there's one at all), but while I was filling it out, I had some anxiety about not qualifying. Once I found out I did, I was excited to fill out the form, which I'm sure most people who are in debt and using this tool are. By making this offer seem more exclusive before the form appeared on the landing page, I'd bet that Bills.com increased conversions pretty significantly.
Open-ended experimentation. This approach is similar to closed-ended experimentation except that more variations will be added for testing and experimentation will not stop when a winner is found. This method is used by large corporation to dynamically improve their conversion rates and improve user experience. Landing page can also be adjusted dynamically as the experiment results change to further enhance user experience.