Discussing three options and select one for bounty.
At Grin meetings, discussed the possibility of introducing a Bulletin Board system for Grin as sugested by @satoshocrat.
The purpose of a Bulleting board is for users to be able to share information while they are offline. These are not non interactive transactions, but are a solution that allows those users who do not like having their wallet
online, or those who do not like to share their slatepacks via email or other known channels, to share that information.
Details at forum;
GRIN Bulletin Board Bounty