Amazon emailed me to say I might be interested in this rock pick on sale, based on my previous purchases. The only connection I can see in my purchase history is a pair of Estwing safety goggles that I bought, oh, 10 years ago?
I'd never looked at my entire Amazon purchase list before (you can find the whole list under "Improve your recommendations"). It totals 57 items over 12 years. I guess if I'd bought more stuff, they'd have a better idea of what I might want.
What's your Amazon tally?