People who demand large message size limits rarely understand the limitations of the email transmission.
Because of the MIME encoding used when sending binary attachments, your files expand 33% when sent via email. In other words, a 15MB attachment requires 20MB plus the message text, plus message headers.
When you carbon copy 20 of your friends & coworkers, a separate message is sent to each. 20MB x 20 = 400MB. That's half a freaking CD.
If 5 of those friends are on the same small company email server, downloading those messages saturates the entire bandwidth of their T1 data line for nearly 9 minutes. Because each message has separate headers, it isn't easily cached and gets completely downloaded by each recipient.
Compare this to uploading the same attachment to a web server, FTP server, file transmission service like YouSendIt, or video streaming site like YouTube. One copy is uploaded. The download is typically 8-bit so minimal expansion factor. The small business' network can cache the content, so it's only downloaded once then fetched locally from the web caching server.
Bottom line, sending a large attachment via email is relocating using the U.S. Postal Service as your moving company. It is painful, limited, and expensive.
Go back in time with Street View
18 minutes ago