Does the Google Earth API require a key?

Version 3 of the Google Maps API doesn't require a key any more. Does the Google Earth API? If so, why the difference?

Update: The Earth API does require a ke开发者_开发问答y, though I still don't know why.

The API key is not required as of version 6 of the Earth Plugin, though the documentation was only changed to say this recently to ensure that the number of users stuck on a version pre-6 had a chance to update.

When 6.2 came out in Jan 2012, the docs were updated to show that you no longer need a key.

The API key appears to be reuqired for version 6.0.2.2074, at least, when it is invoked from a website hosted HTML file. It does not appear to need it if you navigate to the same file on a local drive. Please correct me if I am wrong. This answer would appear to be at variance with the previous answer claiming it is not required with version 6

The message produced with this version of the plugin is "The Google Maps API key used on this web site was registered for a different web site. The developer of this web site can generate a new key here." and "here" is a general link to the google developers site.