Hey, I just want to know that what's the ultimate keyword research addon in Mozilla? The one which is both efficient (means that it doesn't slow down the browser) and effective as well?
Maybe you mean seoquake plugin? No doubt it was an awesome tool, but when google changed some algorithms, and yahoo site explorer closed, There are some troubles unsolved. For example the claim that new source of link/linkdomain (analog to yahoo link domain) will be taken from semrush, but it doesn't work for no reason.
Best paid ones are Market samurai and Longtail pro. If you are serious about keyword research use one of them, they both have trail period and I think Market samurai can be cracked, but I personally use Longtail pro.