David Engel and Brian Rucker found themselves wondering about mobile versions of websites. The system they built to detect whether mobile sites are displayed for five mobile operating systems is now available as the Company Data Trees Mobile Website Detection API and is the first "branch" of their new venture, Company Data Trees. When Engel and Rucker ran the top 200 sites (according to Alexa), they found about half have no mobile site, including LinkedIn and PayPal.
