Early in my time there we had a major, unexpected load spike in the middle of the day. People where tweeting like crazy, breaking records for volume, etc. The system was groaning under strain but it mostly held. Turns out Michael Jackson had died. We sustained 452 (or maybe 457, it was roughly 450-something) tweets a second. this quickly became 1 "MJ" worth of tweets. We informally used this to define load the entire time I was there. Within a few months we got to a point where we were never BELOW 1 MJ, within a year I think we had peaked at double digit MJs and sustained several even in the lowest periods. Before I left we had hit 1 MJ in photo tweets, etc.

Around the time I left we did something like 300 MJ's per second, and I was only there 3 years.