[mweatherill]

A primary reason why a site wouldn't support PMs to [e-mail] is that there is no access control. The address would get spammed too easily from senders with no affiliation with Hacker News. The current mechanism of only supporting messaging within the site limits this.

[mkramlich]

Sometimes it's interesting to think about how much better the world could be if we could design things without worrying about griefers.