In Safari, a feature I really like is that flash plugins are automatically blocked by default and you have to click in order to start the flash plugin (see, e.g., http://mac-fusion.com/manage-the-safari-power-saver-feature/). I found, however, that it prevents Google Play's "play music" buttons from working, so I had to temporarily disable the feature (uncheck the "Stop plug-ins to save power" box) and restart Safari in order to listen to music on Google Play.
There is some sort of exclusion list. I currently have 3 sites listed, but I do not know how they got there. How do I add a site, e.g.
play.google.com, to this list?
I don't see a UI to do this, but perhaps there is a way of editing a plist to insert a new entry?