Telstra, which is an Australian carrier, held their "Big Day of free data" essentially giving everyone a 24-hour period with unlimited data that wouldn't impact their bill. That's a pretty cool idea, and one we wish more US carriers would adopt - especially with unlimited data going away. However one user took advantage of the free data day from Telstra, and in a big way.
Posting on reddit as user DrRodneyMckay, this individual used 421GB of data in just one day. That's right, in a 24-hour period he used 421GB of data, and with some hours racking up 143GB of data itself. Looking at the screenshot posted on reddit, about 420GB was used by the Android OS (it's worth pointing out that some streaming services will show their data under the Android OS bundle instead of the app name for some strange reason). With the second app listed being Speedtest.net. Which the user did post a few screenshots of the speeds he was getting, and it was 150Mbps or higher each time. Speeds we all wished we had on our mobile network. This user downloaded all sorts of seasons of TV shows, which accounted for the high data usage - although downloading 25 seasons of 'How It's Made' must have been pretty quick.
During this Big Day of Free Data from Telstra, the carrier saw 1,841 terabytes of data pass through their 4G network. Due to this free data day, many parts of Australia did see slower speeds on Telstra's network. This was likely due to a number of users using a lot more data than they probably should have. Including the user mentioned above. However, now Telstra can see what needs to be fixed in their network so that when some users use a lot more data, other users don't see slower speeds, or no speed at all.
We've seen some crazy data usage amounts for a 30-day period before, but never this much in a single 24-hour period. That's quite the accomplishment, however he was tethered to his computer for most of this. Additionally, Telstra did not have any restrictions on how customers could use their data on their Big Day of Free Data for Valentine's Day.