alt Hacker NewsA long, long time ago ... there was a browser extension or maybe an iframe, that allowed you to "comment" on public websites. Of course you weren't really commenting on the actual website, just some form of overlay. Anyway, it quickly devolved into lawsuits and rude comments if I recall correctly.
Do you remember any details about the name of the software, or the cause of the lawsuits?
I had a similar idea, funny to hear it's been done and ended so badly.