Web merchants routinely leak data about Bitcoin purchases
I'm a co-author of this paper. It's available here: https://arxiv.org/pdf/1708.04748.pdfThe surprise here isn't that Bitcoin isn't perfectly anonymous. There are two new findings. The first is the extent to which your Bitcoin payment details get leaked to third party trackers. I've been writing about the excesses of third party tracking for years [1], and I'm pretty jaded, but the extent of the leaks surprised me.The second main finding is that CoinJoin isn't enough to protect yourself. We tested this on our own transactions, but also by coming up with a way to identity essentially all existing CoinJoins on the blockchain and analyzing their anonymity.[1] http://randomwalker.info/web-privacy/