On: Full-disclosure – Administrivia: The End

[nly]

You then can't filter or delete spam, which far outweighs legitimate mail.

[Aqueous → nly]

You need to pay BTC in order to store in the blockchain(i.e. you can't send 0.00BTC transaction to someone.) That should go pretty far in eliminating spam. Then again it might be too high a barrier for legitimate posters.