Hi all,
Thanks for all the comments, they are very much appreciated. I'm going to write a follow-up piece soon - if you want to send me feedback directly, please feel free.
I tend to agree with the point that NPM isn't a big enough target yet to make writing subtly malicious modules worthwhile. However, I don't think that's particularly reassuring. I also suspect that more people are using SSL/TLS directly from node (and running as root) than you might think. Malware targeted at developers may well become more of a big deal in the future.
The issue is generic with most package management systems. What I really wanted to talk about was why malware is an apparent problem in some projects and 'ecosystems' and why it isn't in others. The general consensus when talking to other security researchers is that a decent package management system is vital to security. Much like the Google Play store is a key part of Android security. However, NPM (sadly) doesn't really support that hypothesis, as (when I wrote the piece) it wasn't obvious how to report bad modules.
I'd also like to applaud the work that nodesecurity.io is doing - it's a very worthwhile project.
Best wishes,
John