I have a galaxy s4 also. I have noticed on 2 occasions that an item I have talked about ( but not searched for whatsoever) has ended up on my feed as for sale on facebook.
A few months ago a FReeper posted that he and his brother were sitting in his office having a conversation discussing a certain subject. Subject never had been researched online. About 15 minutes later, he was seeing pop-up ads for that exact item.
Twice I’ve had phone calls from companies right after visiting their homepage. We have one of those wireless plug in the wall devices for regular home phones.