Re: [ANN][XRB]Cryptocurrency's killer app: RaiBlocks micropayments

i would like to understand how rai is preventing spam if it has no fees?

Good question, I also want to know,

AFAIK
all transactions need small PoW to process txs
the PoW in RaiBlocks is simply used as an anti-spam tool

more : https://raiblocks.net/media/RaiBlocks_Whitepaper__English.pdf