Must read changelogs properly more often- thanks for alerting me to this. Debating now whether to leave it on or off for clients when I sort their machines out but I have got lazy this year and switched to automated installs (got to love mozbackup) of all the addons and such. Also I guess I have to wonder what will slip through when wound together with my usual selection of ghostery, requestpolicy, beef taco, noscript and greasemonkey not to mention with flash finally thinking about going downhill.
I do hope however they achieve their goal of making adverts a bit nicer for all concerned, I wish there was a better/easier way of monetising websites but I suppose I have to be a realist.