emailing Amsterdam means in slang: This is the process of checking your email while in a vehicle that uses public wifi. You will need to first find an open Wi-Fi network and then log in using DHCP. Then, you’ll have to frantically try to surf the internet or check your emails before it is lost.
This is done usually quickly at the stoplight, mostly because of boredom or curiosity.
(in Slang Dictionary, added by Dominic Faulkner)