Re: Is this app any good?
Good questions. Downvoters: GFY.
These are the salient facts (source: wikipedia)
- E2E-encrypted one-to-one and group chat
- via central servers run by Open Whisper Systems
- smartphone (Android or iOS) required for signup
- phone number required for signup verification (need not be associated with the phone)
- "desktop" app available as a Chrome extension, currently preview release, does not support signup
Certainly has its limitations but sounds like a decent alternative to non-E2E chat apps like Slack, Google, Facebook, Whatsapp.