Which partially explains how they managed to have a 10 Mbit port at an internet exchange. Although that seems weird even for 2010? I assume this would be a 100 Mbps or Gbit port artificially throttled to 10 Mbps?

That said, 50 Mbps of traffic sounds like a non-issue for someone like Cloudflare, so I'm not surprised they took the prefix.

Edit: A post by Cloudflare (linked in another subthread here) mentioned 10 Gbps of traffic at the time Cloudflare started using it. Which, as it would be spread over multiple locations, is probably a relatively minor annoyance.

It seems like it's MB to Mb, but still it feels like a small number even in 2010 standards

Has to be a virtual network right? The throttle was for safety not cheapness.