I'm planning to organize a massive giveaway for new memo users from other platforms when Pings @, Hashtags # and private messages (encrypted or not) will be fully functional on memo.
@TrashPoster those are all planned for medium term. Also have plans to start new accounts off with a few sats but no tipping or key export until they fund it.
Encrypted data isn't necessarily that big. The chances of your data being cracked is about equal to chances bitcoin signatures are cracked. Quantum computers in the future may though.
The NSA is keeping a record of everything sent over ISP channels. Someone at least potentially has these messages anyway. Anything sent over the internet has this problem.
Keyport is doing that. 184 caracters is not a problem, you just have to send the message in multiples transactions, and encrypt it with the public address of the receiver