AdBlock Plus.
Legit AdBlock .

"Adblock Plus" from "Wladimir Palant" is malware, use "Adblock Edge" or "Adblock Lite"

"Adblock Plus" (rogueware)
https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/

Adblock Edge (legit)
https://addons.mozilla.org/en-US/firefox/addon/adblock-edge/

Adblock Lite (legit)
https://addons.mozilla.org/en-us/firefox/addon/adblock_lite/

Also see:

"Chrome Rogue Browser Extensions"
http://insurgencymod.blogspot.com/2012/11/pro-tip-rogue-browser-extensions.html

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