there are no authorisation, phone number verification or fb login - only user's device ID
That does not sound anonymous at all, if you know the device ID, you are totally trackable. Maybe change your pitch to "pseudonymous"? Anonymity is important and this is not actual anonymity.
thanks. we'll consider that.
just for information apps with phone verification use "anonymous" in description too. we are way more anonymous than secret and many other out there.