Thanks for the link, that's a fascinating paper.

One thing that drives me nuts about that paper format (a LaTEX template, I guess) is that it doesn't have a date. And this happens a lot. If the topic was an abstract mathematical concept, evergreen and timeless, then the date isn't so important. But a paper about spam that is vague on the date? I don't understand. That field is always changing, and I presume the economics are changing, too.