LukeW | “Mad Libs” Style Form Increases Conversion 25-40%: “A while ago, I came across a unique registration form built by Jeremy Keith for his audio sharing site, Huffduffer. Though it asked people the same questions found in typical sign-up forms, the Huffduffer registration form did so in a narrative format. It presented input fields to people as blanks within sentences (Mad Libs-style, if you will).
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Ron and his team ran some A/B testing online that compared a traditional Web form layout with a narrative “Mad Libs” format. In Vast.com’s testing, Mad Libs style forms increased conversion across the board by 25-40%. You can see a before and after view of the Contact Dealer forms where they ran these tests below. “

Quite tempted to use this approach myself for some sites.