The closest we have to inline comments is the Google Docs interface and StackOverflow uses and exposes revisions, but neither has a self-hosted version.
The closest we have to inline comments is the Google Docs interface and StackOverflow uses and exposes revisions, but neither has a self-hosted version.
I'm not sure if there was a public service, or it was more of an Intranet type thing. I do recall seeing the Discuss button in IE much later then IE5, and a quick search shows plenty of people asking what it is, so it mustn't have been too obscure a feature.
Should anyone be interested in experimenting/prototyping a system like this - I'm up for a weekend hack or so. My contact information is in my profile.
You can leave a comment on a particular line in the diff and the comment will be collapsed if you update the code and the diff gets outdated, but the UI will still show you the original chunk you commented on.