'50% of transactions were fraudulent' when Steam accepted Bitcoin for payments
Context on what I believe they mean by "fraudulent".Steam back in the day used to accept 0 confirmation bitcoin spends. This means that the transaction has been gossiped on the bitcoin p2p network but had not yet been mined into a block and thus had minimal finality guarantees. Steam could see that they were going to receive a bitcoin payment (when the transaction was mined into a block) and would credit the users account instantly for a better purchase UX.Turns out anyone with some deeper understanding of bitcoin could construct another transaction spending the same bitcoin back to themselves before their original transaction was ever put in a block. The bitcoin community moved away from accepting '0 conf' transactions pretty much everywhere because of this reason.In fact the high fee era (2016-2018) saw many wallets incorporating this "double spend" feature into their wallets. This is known as RBF, "replace by fee" and is really useful when you need to bump your transaction up the queue. You replace your old transaction, that is waiting to be mined, with a new one that offers a higher fee to incentivize miners to add it to a new block.I think its rather unfortunate that 0 conf transactions were written off so quickly. There are many context where a 0conf tx makes sense, mostly IRL. But, if you are running a business online and you don't trust you customers you should wait 3-6 blocks after the transaction has been mined before delivering your goods.