uBlock Origin for Firefox

An efficient blocker: easy on memory and CPU footprint, and yet can load and enforce thousands more filters than other popular blockers out there.
Usage: The big power button in the popup is to permanently disable/enable uBlock for the current web site. It applies to the current web site only, it is not a global power button.
Flexible, it's more than an "ad blocker": it can also read and create filters from hosts files.
Out of the box, these lists of filters are loaded and enforced: EasyList; Peter Loweâ??s Ad server list; EasyPrivacy; Malware domains.