"Sites that support HTML5 will default to a clean HTML5 experience. In these cases, Flash will not even be loaded, improving performance, battery life, and security. For sites that still depend on Flash, users will have the opportunity to decide whether they want Flash to load and run, and this preference can be remembered for subsequent visits."
I'll take a look at it some time.
Personally I've been blocking flash from running unless I give it permission for several years. Flash adverts are where most of your browser malware comes from.