It is written in Python and supports features such as multi-tenant operation, built-in Disqus import (with an API for other comment sources), and a simple moderation queue with various notification mechanisms including SMTP. It is also built for smaller sites and uses a local SQLite database for its comment storage.
- Unfortunately it only supports the md5-hash mechanism, which is a privacy issue.
- Also it doesn't currently provide libravatar federation support
Unlike Disqus, Isso does not allow specifying a thread ID separately from the embed page URL, and all comment reply emails assume that the thread ID itself is the URI/path for the comment thread's page, which is a problem when using it for private posts or in contexts where post URLs can change. fluffy uses a page redirection mechanism to keep thread IDs unguessable and portable.
The administration/moderation mechanism is quite limited; there is no way to mark comments as spam (only delete them), the admin UI does not provide a text search mechanism to actually find specific comments to edit, and the moderation queue is all-or-nothing (i.e. either all comments are held for moderation or none are).
And some gripes from fluffy:
- The code isn't written in a particularly-modular way, so extending it with more functionality is rather difficult. The primary author/maintainer also seems to not be very active in the project at this point.
- The admin documentation could also use a lot of work, IMO
- fluffy has migrated to it as of 2019-08-04