Ask HN: What's behind “I was checking your website on behalf of this email”?

Over the last few months this type of spam has exploded in my inbox: messages that begin with "I was checking your website on behalf of this email". I presume it could be the latest form a spam that is momentarily effective. It's also not untrue, by virtue of being meaningless (and a little deceptive).

In the last 2 days I've received ~30 spam emails (that beat my spam filters), ~90% of which began with that message