Firefox “click to play” means Silverlight, Java, most plugins won’t run automatically
Mozilla is taking an interesting approach toward improving stability and security in future versions of the Firefox web browser. Starting soon, websites won’t be able to automatically load most plugins unless you click to enable them.
If you visit a site that requires Java, Silverlight, or Adobe Reader, you’ll see a note asking if you want to enable that plugin to run. those plugins won’t just work out of the box — although you will be able to configure Firefox to run plugins automatically if you don’t want to deal with the hassle of clicking a button every time you load a new website.
In other words, while plugins will be disabled by default, users will be able to decide how they want things to work.
There are some good reasons for the new “click to play” approach. Mozilla says that poorly coded plugins are responsible for more browser crashes than anything else. Security holes in plugins can also leave your browser (and your entire computer) vulnerable to malware.
Interestingly, Mozilla has decided that the latest version of Adobe Flash Player can run automatically — presumably because it’s relatively secure… and also a plugin that’s required in order to access an awful lot of web content.