[haute_cuisine]

It's most likely already installed when you send an invite to someone and they already used to how it works. It just works most of the time, well, besides slightly buggy text editor and almost non-working calls.

[EGreg]

But so what, browsers are installed too and can load arbitrary websites. Which can implement all that stuff too. And threaded forums like Discourse are far better.

[haute_cuisine]

You still need to register and put your credit card.