AFAICT, "microservices" is exactly SOA in its original sense; my guess is the rename is because SOA has become so attached to particular XML-based implementations and standards (e.g., the WS-* series of standards).

This. Also SOA means STD in Dutch, so we don't want to use it that often ;)

No difference, just a new name. Not so bad I guess, however I fear it will cropper when vendors leap on the bandwagon again and start sell inappropriate tools and frameworks badged as Microservice and we can start the process of renaming again.

That's great news for vendors and consultants who jump on the bandwagon though :).