Continuing on the "portability theme" this week: the folks at StrataVarious, a Boston-based data visualization company, have put together this excellent side-by-side comparison of the leading online mapping APIs: Google, Yahoo! and Microsoft. Concise use of space to give a quick sense of what the key similarities and differences are in code, UI controls, markers, behaviors, and other attributes. Continue onto the subsequent pages to see more code comparisons and diagrams showing the structural layers of each map. Very well done.