Thanks. What are your thoughts about releasing a free web-based eBook and selling a download copy? This would be similar to 37signals' Getting Real: you can r

Thanks. What are your thoughts about releasing a free web-based eBook and selling a download copy? This would be similar to 37signals' Getting Real: you can read it free online, or purchase a PDF copy. Do you think this would be an effective marketing strategy, especially for an author's first book?