Most likely you were looking at things on the internet that implied a need for masking tape. For example if you looked at blogs about home remodeling and inter

Most likely you were looking at things on the internet that implied a need for masking tape. For example if you looked at blogs about home remodeling and interior painting you could be generating signals of intent that suggest you might be in the market for masking tape. It's not as obviously creepy as "AI wuz listening to me! OMG Skynet!". But it is creepy that intelligence, vast, cool and unsympathetic is working to create a model of you to help its masters intercept your every purchase impulse.