[koonsolo]

Because nano has free transactions, a big concern was indeed spamming the network because transanctions are free (as in you pay no nano). But since each wallet has to calculate their own blockchain, the prosessing power is purely on the client side and so not free in that sense, which limits the spamming to the processing power you have.

[tromp]

Recent spamming [1][2] has seen nano ledger size balloon by nearly 50%, negatively affecting full node Initial Block Download times as well as archive node disk space requirements. The PoW requirements go up with network congestion, but at this rate of 5-8 tps are quite minimal.

[1] https://nano-faucet.org/stats/

[2] https://nanocean.org/ (Click on Live Stream)