"People" have, but most of the internet-using population haven't. Not saying this is the best method, but don't be fooled into thinking that everyone is aware of what's going on.
Why? Are you saying the actual popup doesn't communicate the proper information? I said in another comment, my website is for finding and discussing new music. My users certainly don't have to be technical people. It would seem, seeing this message might very well give them some information they've never seen before.
First - When was the last time you read a popup? Hell, who doesn't have a popup blocker now?
Second - This is not information - "Cable companies could make this page so slow, it would still be loading..."
How? Why? What is this about? There is no information there. On top of that, many ISP's already are (people are familiar with throttling regarding their mobile data plan) so this doesn't even say that anything is changing.
"People" have, but most of the internet-using population haven't. Not saying this is the best method, but don't be fooled into thinking that everyone is aware of what's going on.