Adblock Plus on Thursday announced that the open source community had created a filter to neutralize Facebook's latest offensive in its ongoing battle with ad blockers. Any Adblock Plus users who want to implement the workaround will have to update their filterlists manually. "For this round of the cat-and-mouse contest, looks like the mouse won," said Ben Williams, spokesperson for Adblock Plus developer Eyeo. Facebook on Tuesday began serving up ads that circumvented desktop users' ad blocking software.