I wanted to perform a little unscientific information gathering, I'm working with a small group who think they're being specifically targeted by these, while I think it's more widespread and opportunitistic.  If you've recently received these no content probe emails, or a simple "Hi" message, please send a simple comment below in this format:

• Industry
• Order of magnitued in size (e.g. <10, <100, <1000)
• Sending domain

    Feel free to use our comment page to add extra analysis comments here: https://isc.sans.edu/contact.html