[antcas]

What rule does it break?

It's not immediately clear, but if you log in (at the top of the page) you can log your own expenses to a public transaction feed.

And you can participate in the main experiment by commenting on OP's transactions.

Seems like a cool and valid Show HN to me.

[dang]

I don't see how people can try this out. It looks like a closed beta with a signup page?

[pvg]

I think it had a beta notification form thingie when posted, then other problems but now it looks like you can log in? It's getting spam and abuse though so it's maybe not quite at the public trying stage yet either way.