[underyx]

>My mates got Bitcoin ads just after I've spent most of an evening explaining what it was to them for the first time.

1. You most likely have had thousands of cases when you talked to people about something and they didn't get an ad for the topic afterwards. One care hardly proves anything.

2. In Bitcoin's case, it's even more likely that this would happen coincidentally, since it was a temporary fad that got popular over a short period of time, during which time you had an increased likelihood of explaining Bitcoin to your friends, and your friends had an increased likelihood of being served Bitcoin ads, even independent from each other.