This is a duplicate of a question I posted at Stack Overflow: http://stackoverflow.com/questions/10760845/contiguous-regions-in-web-map-services.
I'm working on an application that must calculate routes through South America, specially between Brazil and Colombia. I've found that Google Maps does not consider the hole continent contiguous: Venezuela, Colombia and the Guianas are "closed" for routes that crosses their borders, although it's possible to calculate routes within these countries.
How this analysis could be duplicated to other web map services? So far, Bing and Yahoo!, Nokia Maps seems very connected, except from Colombia to Panama.