I was surprised to see a Homegroup icon on my desktop this a.m. Should I be concerned?

Apologies if I posted to the wrong community board. I am new (first post). This morning I awoke to see an icon for a feature called Homegroup on my desktop. I am not aware of anything I did to put it there and a cursory review of info on the internet indicates it is a feature of Windows 7, which I never had (I use Windows 8.1 64 bit). I opened it and clicked "Leave Group" or something to that effect. My biggest concern is that it apparently is a feature that allows sharing between computers. Also, I posted my first ad on Craigslist  yesterday. Could that be relevant? Thanks in advance for any insight.