The bandwidth and rate limitation features of steem are very interesting concepts in the realm of "spam" and "attacks".
Because steem is weird and does not have transaction fees, the bandwith and ratelimits do an interesting job solving these problems.
In Bitcoin there is no such thing as a spam transaction: only fee paying and non-fee paying. If someone is sending a lot of transactions, but paying fees, it is not spam.
Really wonder if tx fees and the like would have been better for steem.