I have a system like this, but slightly different.

Entries are structured as a DAG, where an edge between nodes indicates some degree of causal dependency. Each entry has a prediction market associated with it. Every entry is intended to be either a statement of existing fact, or a plan that can succeed or fail.

The software is pretty awful, though. It's written in PHP and is mostly unstable. I started rewriting it a long time ago in Python with Flask and haven't gotten far mostly due to a lack of time.

This is less for discussion, and more for planning. It was originally intended for group strategizing, but was never really used.

This will never be popular, though. You'll definitely not get anyone normal to use it. There are plenty of systems like this that exist (structured debate sites) and they're pretty tiny.

Also, using voting as the metric is pretty shitty for obvious reasons. Plenty of people agree with false things; especially rationalist/LW types (it's easier to convince yourself of what you already believe if you're better at convincing in general).