Behold, the Firefox Wall of Shame. Actually they're calling it the Slow Performing Add-ons… list, I suppose. Either way, the following add-ons are likely to NOT be happy with this situation. The reason Firefox has created this list is to essentially make the slowest functioning groups feel so terrible about themselves that they either amp up their developing to create a better experience - or of course, hang themselves in shame.
You'll notice Firebug, an add-on that helps people make their webpages function faster - oh the irony. Then there's a slew of oddities that more than likely have been abandoned by their masters to rot in a slowly degrading prison of dead pixels and hashtags. Furthermore, Mozilla wants you to know that it's these evil brands that are slowing down your Firefox experience, not the browser itself.
They chop the heads off the offenders with a simple "If you think add-ons might be the reason Firefox is lethargic, check the list below for some of the biggest bottlenecks. And remember, for best performance you should disable add-ons that you no longer use regularly." Firebug and FoxLingo translator and dictionary slow down your Firefox day-to-day by a monstrous 74% - watch out!
NOTE: The most ironic addition to this list is of course FastestFox - Browse Faster. Oh how marketing can take us for a ride…