Firefox has had a click-to-play plugins feature for a while now. It's a great feature too, enabling users to run plugins only when they need them, keeping them safer and keeping Firefox lighter and faster. Still, the feature has to be enabled by the user.
Mozilla only intervenes and switches it on by default for older, vulnerable versions of plugins such as Flash or Java, to protect users.
That's about to change as there are plans to make click-to-play the default state for all plugins added to Firefox except the very latest Flash.
Currently, Firefox loads all plugins requested by a website. This takes a toll on performance and it can be a security threat.
Once the change is implemented, Firefox will not load any plugin unless the user allows it or if the site has been whitelisted.
This includes older Flash versions, Java, Adobe Reader, Microsoft Silverlight and everything else except the very latest stable Flash version.
It's a big change, but it should be to the benefit of users. Currently, it's hard to imagine any significant portion of Firefox's user base turning on click-to-play plugins by themselves.
It's precisely the users less likely to enable the feature that are the most likely to run into malware or not realize why Firefox is so slow.
That said, the move could break quite a few sites, sometimes in ways not obvious to the user.
But this is why Firefox displays a big, popup notification every time a plugin is blocked, to make sure users realize why a site may not be loading.
Mozilla will take its time implementing the change. First, old version of Flash, 10.2.* or older, will be blocked via click-to-play with newer versions gradually added to the block, except, eventually, for the very latest version.
During that time, Mozilla will finalize the click-to-play UI. After that, every other plugin beside Flash will be added to the block list, no exceptions.