Making BitMessage into a BitPostage alt-coin + Distributed Longterm Storage

[greBit]

Could nodes just decide to store loads of data, profit from mining / dividends but then decide to not bother responding to requests for that data?

Since bandwidth can be quite costly, this would be quite a rational thing to do.

How to have economic incentives to prevent this behaviour?

[TierNolan]

Calculate the hash of the previous block concat with the full message

The whole point of POW is that it is easier to check than to create.

How would simple verification nodes check the chain?

[bytemaster]

This system is not scalable because all nodes require all information in order to validate the chain.  After running the numbers it became clear that the maximum user-base-per-chain would be too small to support a currency.