[leephillips]

'The web is littered with the corpses of "comment on any website" apps.'

There is one "comment on any website" tool that has existed from the beginnings of the web and still thrives. The way it works is, you put the comments on your own website.

[michaelmior]

Do you mean, post comments you have about another website on your own site? Definitely works, although obviously harder for others to discover your comments compared to a single commenting tool which everyone used. Although I'm sceptical such a tool will ever exist.