We just increased our book sales by 42% thanks to user feedback and about 60 minutes work. Getting rapid results with minimal effort like this is our main goal in practising rapid web development.

The improvement we made was obvious: we started selling our Web Developers' Checklist book, in PDF format. When we launched the books' website, we ruthlessly cut out all the nice-to-have's and launched the site just 2 days. The PDF format was one of the features we cut out, opting for paperback only.

Over the following months, quite a few users requested a digital version of the book. You can't beat user feedback to give you clues for improvement, so we investigated our options. It was a toss up between:

• Google Checkout - most profitable with costs of about 3% but we'd need to spend a day or two creating a simple fulfilment system.
• Lulu - most straightforward with set-up in minutes but they would take a cut of about 18% per PDF sold.
  

We didn't know how popular the PDF would be, so we saved ourselves the time and chose Lulu. We knew we could always switch to Google Checkout (or PayPal seeing as Google Checkout just hiked their prices) and increase our profit margin later.

Six weeks later and total sales have increased 42%. Of all the books sold, 53% were paperback and 47% were PDF, so not only has PDF increased total sales but it has stolen some of the share from paperback. That was a feature worth implementing.

Buy the book: Tick My Boxes - the web developers' checklist.