About 10 years ago, I wrote the original LessWrong 1.0 anti-kibitzer. The original rationale for creating it was as a de-biasing tool to aid in judging ideas by their contents, rather than their author or popularity. The original post goes into the rationale for its creation in more depth so I won't repeat myself here.
As such, I went back and updated it for the modern site. Follow the link to find the UserScript, some screenshots of it in action, and installation instructions. I have also added an additional feature which replaces the usernames with colorful bars of different lengths and colors. This makes threaded conversations easier to follow, as it enables one to tell when two comments are written by the same individual.
Let me know in the comments if you find any bugs or have any feature requests.