[seanmcdirmid]

> because their comment is anonymous to the author and won't be available to the readers

You can make comments on your papers available; there is nothing against that. I really think, however, peer review comments should actually be published with rejected and accepted papers (at the author's consent, not reviewers) so that conferences can be more transparent.

[esbio]

You can, but 1) there's no official channel 2) nobody will do it if they are not forced.