For static sites, a service that takes comments and pushes them to the source repo for the site (or an extra comment-only repo for security and build-performance) could also be interesting.
On the other hand, a repo history is normally immutable (with force pushes on rare occasions), and comment spam is way to common. Do you really a repo with all the usual link spam in its commit history? In case of public hosting it may trigger some spam filtering automation and block the repo/account. While perfectly possible, I'm not sure a DVCS repository is a well-matching concept for storage here.