[harwoodleon]

This paper is very considered. But it does not consider that these questions have all been addressed in other cryptocurrencies like Nano (nano.org), which is a far more usable system than Bitcoin. Especially now that “Time as a currency” spam mitigation measures are being rolled out.

[billytetrud]

True, the paper is just about bitcoin specifically. I've read through Nano and the spam problem was #1 in my mind. It seemed to me that there was no possible way to prevent spam in Nano without turning it into a strictly-worse form of cryptocurrency than other proof of work systems. So my determination about Nano was that if it maintained its current course, it would flame out (transactions would increase without bound until no one could run Nano nodes) OR that they would have to change course to something like increasing the transaction PoW, which would increase the work done on end-user machines to the point where its very cumbersome (slow and expensive) to create a transaction.

I'm curious to know what "time as a currency" is and how it solves the spam problem. Do you have a good link that explains?