Monero/Aeon developer smooth, quoted below explains the encrypted messaging system he is currently researching:
There are many ways one could implement messaging, but I don't favor storing p2p messages on the blockchain itself. Encrypted is even worse, in a way, since that can't possibly be of any benefit to anyone other than the specific recipient. (At least if you store bible verses or dick pics, there might be a few people who are interested in that.)
I would propose something like:
Create and submit a small transaction that pays a fee and includes a hash.
After the transaction is successfully mined, you may submit a message packet up to some maximum size (for example 32 KB) that matches the hash (assume the message is encrypted, but it wouldn't necessarily need to be) into the mempool, where it will be stored and relayed to peers. Once the transaction reaches a given depth in the chain (for example seven days; 5040 blocks), the hash expires and the message may no longer be submitted or relayed.
It is true that it is extremely difficult if not impossible to prevent use of the blockchain for storage of arbitrary data that does not benefit most of the people incurring the cost of the system, but providing a useful mechanism that does much the same thing in a less harmful manner is a good way to discourage it.
Possibly the lifetime and allowable size of the message could be a function of the fee paid, but there is no good way to set the fee, nor a good way to compensate the node operators for storing and forwarding it, so the suggestion of a fixed life and size is intended to limit the cost to something reasonably negligible.