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.
When Google first launched its location-sharing service, Latitude, developers were left wondering how to access their users' data. Now, over a year later, we finally have a Latitude API. But we also have a number of other similar services that have better traction and are arguably more fully featured.