Which app works best
YIM - Yahoo Instant Messenger - doesn't exist anymore
Kik still exists
Wickr doesn't exist anymore
Session is new and is similar to what Wickr was.
There's also Telegram and Signal, but they require registration with a real phone number.
Wire requires registration via an email address.
Threema is not very well known but has a lot of positives, but unlike the others it isn't free.
Teleguard is not well known, but has a lot of positives.
Discord is also used by some people.
Kik doesn't require any personal information to register an account, but there are questions about how secure it is, although it does use end to end encryption. Apparently it is possible trace users via IP address.
Session doesn't require any personal information to register an account, uses end to end encryption via Tor, and appears to be more secure than Kik. No information about chats is logged. It is based in Australia, which is one of the "Five Eyes" countries, but since it logs no data even if Session was compelled to hand over data there would be nothing that could be provided that would identify a user. Currently Session has passed a number of independent security audits, so it should be completely safe to use.
Discord requires an email address or phone number to register. Messages in Discord are not end to end encrypted, so it isn't very secure at all. Not recommended.
Wire uses end to end encryption, but your identity can be traced with some effort.
Telegram does not use end to end encryption unless you enable "Secret Chat", and also your identity can be traced since you registered with your phone number. Telegram also logs your IP address and other metadata and has handed them over to governments. Not recommended.
Signal uses very secure encryption, similar to Session, but your account lacks anonymity since your phone number is known. I have heard that there are ways to get around that.
Threema is very secure, doesn't require registration via phone or email, but costs money.
Teleguard is very secure, does not require registration via phone or email, and logs nothing. I have never used it.
I definitely do not recommend Telegram or Discord.
Whatsapp should not be used as it is owned by Facebook/Meta and although it uses end to end encryption your metadata will be logged and handed over to governments on request and probably also sold to advertisers.
