Weird Icon Appearing on Disk Drives

This morning when I turned on my PC, I noticed these 2 weird icons appearing in front of my two drives (local, and backup disks). The 2 icons were not there before, can someone explain what they are? They look like the standard Microsoft User(s) icon, but why are they suddenly/randomly appearing?

Here's an image of what I'm talking about.

It looks like both drives are set for sharing.

That makes sense, I recently enabled them for sharing. Thanks very much for the reply.

In fact, I can confirm, you are right smufercom, those icons are indicators that the drives are both set for sharing. I enabled sharing on my laptop's drives just now, and the icons just appeared.

Again, thanks for your insight, it cleared up the confusion I initially had with regards to the icons.

I think they started that in XP if I recall, and your most welcome glad I could clear the air.

These come from Classic Shell. There is an option to set this icon overlay to shared folders (which Microsoft natively removed from Win8 - for whatever reason).