Never faced this situation before Avast WebRep plugin automatically adds “WebRep Overall rating” text at the bottom of Google+ posts (check the screenshot below) when you respond to your friend’s post. At first you may get confused it is visible only to you but it appears to friends who sees your posts as well. Something annoying not just for you but to your friends and people added you to their Circles as well, FYI Avast v6 introduced WebRep plugin shows reputation ratings for sites and links in messaging applications too.
This is something not wrong with Google+ since in Beta we can expect some bugs, but Avast needs to fix this as they fixed similar issue related to Gmail in the past with program update. I am using Avast 6.0.1203 latest version and Firefox 4 version (downgraded from Firefox 5).
Until Avast fixes this issues you can remove or disable Avast WebRep plugin for Firefox or other effected IE or Chrome browsers.
1. Open Avast User Interface, click Additional Protection>Select WebRep
2. Click “Uninstall” button for Firefox or other Chrome and IE browsers.