Email messages: How large is too large?

[Ross Finlayson <finlayson at live.com>]

As someone who has used the Internet since before it was even *called* the
Internet, I can remember when noone would have dreamed of sending email
messages that were even 50 kBytes in size.  Times have changed, of course,
and now it's commonplace for people to send email messages that are
significantly larger than this.

But how large is too large?  I recently chastized someone for sending me an
email message that was 3.7 MBytes in size.  (I currently get my email
delivered through a POP mailbox run by my ISP, and the 3.7 MByte message
came close to exceeding my quota.)  "That's ridiculous," I argued.  "Email
was not intended for messages even remotely as large as this."

However, I can't help but wonder if I'm being a bit old-fashioned.  Indeed,
times have changed, and message sizes that once seemed absurdly large are
now quite reasonable.

So I wonder, what do people think is a reasonable suggested maximum email
message size these days (for messages sent over the public Internet, not
just within a private intranet)?  Is there a RFC anywhere that lists a
recommended maximum size?  And should email programs issue a warning if a
user tries to send a message that's 'too large'?

	Ross.