When you type in experts-exchange.com in a web browser, theres all the work of resolving the name into an ip address and then your packets are sent from your computer to the EE web server and vice versa, going through routers around the web, right?
Contrast that with an email? I was explaining to someone that large attachments in an email might cause the email to not be delivered as it routes its way through the web. Then I wondered... is the email actually going through mail servers on the web and being reforwarded? Or just routers (on the backbone?). If it's just routers, do they actually care how big the total email is? It's just a lot of packets being sent in the same direction.
ie - is there really a limit to an attachment size limit in email OTHER THAN at the sender or receiver email server? Yes, the sender server or receiving server can set limits to the size of the attachment. But after resolving the MX record and sending to the receiving server.... what could get in the way?