Jared Wein of Mozilla blogged last month about a new feature he was developing for Firefox 14 called "click-to-play". The idea is to block the default loading of plugins like Java and Flash when surfing to reduce the memory footprint and provide protection against exploitation of plugin vulnerabilities.

Continued here:
http://nakedsecurity.sophos.com/2012/05/05/firefox-to-introduce-click-to-lay-option-to-protect-against-dangerous-plugins/