I received two of these emails. I was a little worried about these, but according to Mint, there as no data compromised. Here's what they said on their MintLife blog:
Last night a flood of emails were sent from email@example.com to some Mint users. It was a misconfiguration with our email provider causing blank emails to go out. This was not a security breach and no data was compromised.
Ken Tumin5,471 posts since Nov 29, 2009 Rep Points: 125,634