14 DAY TRIAL // Mozilla is moving ahead with a change it announced earlier in the year and is soon to start blocking all plugins by default in Firefox, with the exception of Flash, and even that only if it's up to date.
The idea is to remove potential security threats and to speed up browsing by not loading unnecessary plugins.
Most of the time, users don't even know they're running a plugin or what it's for. And the vast majority of the web doesn't need a plugin to work in any browser, modern or not, with the sole exception of Flash, which is still ubiquitous.
That's even if Google seems to be going in the other direction and using proprietary technology in Google+ which only works in Chrome.
Still, as of Firefox 26 WIll Block Any Plugin Except Flash">Firefox 24, which is now in the beta channel, Mozilla has started blocking the Java plugin all the time by default. In fact, all Java versions, including the latest one, will be labeled as "unsafe."
What this means is that, with the default settings, users will have to enable the Java plugin by hand for the sites they need it for, either temporarily or permanently. But they will have to whitelist the sites, as they won't be able to allow Java to run all the time for all sites.
Enabling Java where you need it is simple enough via the Click-to-Play UI. Essentially, the plugin is disabled, but you can override that without going into the preferences, but just by clicking on the allow button from the Firefox AwesomeBar.
However, this is just the first step. Beyond this, as of Firefox 26, all other plugins, except Flash, will get the same treatment. Users will have to enable them one by one for the sites that require them.
They will be able to make the changes permanent though, i.e. always load a plugin they need. Users can disable click-to-play entirely and block plugins permanently or, alternatively, allow them to run on a per-plugin basis.