Yeah, Writely is a great counterexample. Their vision and Google's vision were really close, so they integrated well into Docs. And just to show you that techn

Yeah, Writely is a great counterexample. Their vision and Google's vision were really close, so they integrated well into Docs. And just to show you that technical issues are not the primary problem, they were using Windows/C# but managed to port to Google's Linux/Java-based infrastructure and login system very quickly. (Granted, C# is way closer to Java than PHP).