Going by this twitter poster's logic, the reason OP started seeing ads for traveling to Tokyo, is because the ad networks saw OP and his friend had a long conve

Going by this twitter poster's logic, the reason OP started seeing ads for traveling to Tokyo, is because the ad networks saw OP and his friend had a long conversation, and that OP and his friend had both previously traveled to Tokyo previously, and was betting on that subject coming up in conversation, triggering nostalgia, and figured that it might be able to convince one of these guys to buy a ticket based off of that :D