Reeses keeping track

So today I decided to splurge a little on lunch and walked over the the Salem Market convenience store and bought a reece's' peanut butter cup and a kit-kat dark chocolate.

I was initially looking for the "king size" reeces' and didn't even notice the big box right next to me on the top of the counter, derp.

But anyway

Now all of a sudden on FB I'm getting ads for Reeces. WTAF.

How in the holy fuck did they manage to track me

I'm a little creeped out.