While I was in Chrome over the weekend, I noticed avast! also install the WebRep add-on in this browser as well. Further, in Firefox I could only disabled the add-on, not remove. A quick Google search turned up this post in the avast! forums. To remove the Web Rep, right-click on the avast! icon in the taskbar and select Open avast! User Interface then click on the Additional Protection tab. From there select WebRep and click Uninstall next to the browsers you want to remove the plugin from within. You will need to restart the browser(s) for the plugin to be fully removed.