14 DAY TRIAL // Mozilla announced plans to force users to click-to-activate all Firefox plugins, with the exception of Adobe Flash. This change will become official when Firefox 47 moves into the stable channel at the start of June.
Back in September 2013, Mozilla introduced a whitelist for the "click-to-activate" feature which asks users to enable a plugin like Java, Flash, video codecs, and such, on a per-site basis. [Plugins are different from Firefox Add-ons.]
The whitelist meant that a series of plugins were automatically turned on for all sites. Mozilla engineers managed the list of approved plugins, which was hardcoded inside Firefox's code.
For all other plugins, users had to click a popup to activate each plugin, or go to the Add-ons section, to the Plugins option and set it to activate on all sites by default.
The removal of the whitelist means that users will have to turn on all plugins, one by one, on each site they're needed, which is not a big issue since most of them are used very rarely anyway. The most used was Flash, but Flash doesn't have a bright future in Firefox either.
All Firefox users: Bye bye Flash! Good riddance!
In October 2015, Mozilla announced plans to drop all NPAPI-based plugins except Flash. This recent move is part of this bigger picture.
Mozilla plans to remove all NPAPI-based plugins from its core code, and the Foundation says this is scheduled for Firefox 53. Firefox 53 is scheduled for release in the spring of 2017, with the first alpha versions expected to enter the Aurora channel at the end of January 2017.
Flash will continue to work beyond this date and will continue to be turned on by default in all Firefox installs. In the meantime, Mozilla urges developers to start using more modern technologies. The Foundation did not say which, but HTML5 and WebGL are strong contenders.