git as a commenting platform
It is possible to use plain text files, versioned through git as a commenting platform. This is what staticman does. Thomas Jollans has implemented his own version using Flask, called commie . The biggest difference here is that Staticman relies on Github (not git) to create pull requests, while commie can directly commit to a repository (local or remote), effectively making it platform-agnostic.
In any case, both services store the comment information as plain text files, which would make the comments durable over time and transparent.
Note : Commie uses the combination of IP/Browser/E-mail to validate user's identity and allow for comment edits and publish without verification. Django-comments uses a similar approach (comments are sent by e-mail encoded with base64 to prevent hitting the database before verification).