To be fair.
Although this is true for many sites - switching adverts back on is like going back to dial up on some sites - there is another issue that started occurring in the past year.
TLS handshake.
Especially when using mobile internet connection.
I see this on some webpages that hang for 10+ seconds after all the apparent content has loaded, but you cannot DO anything. Even worse, click on a link, and you are stuck waiting for ANOTHER TLS handshake.
Sometimes this will happen 5-6 times before the websites effected, settle down and let you get on with your life.
Biting the hand that feeds IT
