There's nothing new about depending on external parties - if your site hosts ads (or uses an external stats service) you're already running code hosted elsewhere, so you should probably be comfortable linking through to Google (I trust them a lot more than most ad networks). The question is always "do I trust this provider not to screw me over" - Google's developer network stuff HAS to be trustworthy or they'll lose the hearts and minds they've been cultivating overnight.
As for your app becoming reliant on Google's version of the framework, you can always download the JS file they've been serving and host it yourself. You can't get locked in that way.
As for your app becoming reliant on Google's version of the framework, you can always download the JS file they've been serving and host it yourself. You can't get locked in that way.
This misses the point. I'm not concerned about where the file comes from. If breakage occurs with regard to where the download comes from, a few customers get annoyed while you fix it (or even better, you implemented caching and customers never know the difference). That's a normal and expected maintenance issue that you plan for.
What I'm really talking about is the content of the file. If Google fixes bugs or adds features and you don't realize it until your app has become dependent on Google-specific changes, it's not an easy thing to fix. This is a different problem than getting screwed over by ad providers.
Aah I understand where you're coming from. I would be amazed if Google made changes to the libraries they are serving up (since it would undermine the entire concept of the hosting service).
It would definitely seem to go against the motto, right? You need look no further than Microsoft (and other software vendors whose entire strategy is based on lock-in), and assess the probabilities for yourself.
As for your app becoming reliant on Google's version of the framework, you can always download the JS file they've been serving and host it yourself. You can't get locked in that way.