The idea being that one would use regular SEO techniques (reciprocal link building, doorway pages etc.) whilst the other would use actual business methods (press releases, informative user-oriented content etc.) to see which did best.
Thank you for sharing. My definition of regular SEO would not include reciprocal linking with any random site and true doorway pages (not the landing pages you used), but it would include some of the "marketing" tactics you used for the other site. SEO is a buffet and one chooses which morsels to taste. :)