OK, the “evil” part of the title here is really just to get your attention –
it’s the second part that’s the real problem: attachments are over-used.
And over-used attachments? Those are evil.
How are they evil?
Let me count the ways.
Using unnecessary attachments reduces the probability that your
message will be read.
I want to say that it significantly reduces the chances that your
message will be read, but I just don’t have the data to prove that.
But why take the chance unless you really need to?
Here’s the classic case I see all too often. Someone types up a one page
meeting agenda in Microsoft Word and then sends out that Word document as an
attachment to the list of meeting attendees.
Why not, instead, just copy/paste the agenda into the body of your email
and not use an attachment at all?
Several good things happen when you do this:
Your message is more likely to be read. Your recipients don’t have to jump
through any additional hoops to see it – it’s just there right in the message. They
may not even have needed to open the email message, viewing the message in a
preview pane of some sort.
Your message is more likely to be delivered. The presence of an attachment
can be considered a mark against it as spam filters evaluate the “spamminess”
of a message.
Your message will be smaller and be delivered more quickly. This applies not
only to the time your recipient needs to download the message, but also the
time it takes to traverse the internet to get there.
And in case you’re wondering (as I was) a one-page agenda that I recently
received in Word is 20 times bigger than its content alone.
That’s 20 times longer to download, 20 times more disk space, and so on.
Using unnecessary attachments is being rude to your
Consider what you’re doing with an attachment that isn’t needed:
You’re forcing your recipients to download something that’s much
bigger than it needs to be.
You’re expecting your recipients to have the tools required to open
your attachment if they want to be able to communicate with you.
You’re wasting your recipients bandwidth, disk space, and time to
download, store and open/close your message.
If you look at it that way, it all seems pretty rude, doesn’t it?
So what’s a “necessary” attachments?
I’m not sure I’ll ever consider an attachment “necessary”, because as we’ll
see in a moment there are so many alternatives. However attachments can be an
appropriate convenience in many situations.
I’ll make two generalizations for when attachments can be appropriate:
When the message isn’t text.
When the attachment isn’t the message.
And to be clear, both of those are quickly invalidated if the
attachment is too large. More on that in a second as well.
The message isn’t text.
The clearest example might be voicemail or other audio recording: only
sending an audio file as an attachment makes any kind of sense.
Sending a photo or short video to a friend or family member is also a fine
In both of these cases the “message” just isn’t something that can be
represented as text in the body of a message. (FYI: a photo that
appears in the body of a message is still considered an attachment by
both the mail system and for the purposes of this discussion.) Attaching the
image, the audio or whatever else is simply the only way to get it across.
If it’s small enough, that is.
The attachment isn’t the message.
I’m playing a little with semantics here, but the idea is this: sometimes
the “message” is something like “could you review this document”, or “the third
quarter financial’s are attached for your review”. The attachment isn’t the
message. It supplements the message, it’s additional baggage that’s referred to
by the message, but it’s not really the message.
However you choose to think about it, there are scenarios where Word
documents and Excel spreadsheets and other types of documents must be
transmitted whole. Typically they’re scenarios where information in the
attachment must live on after the message has been read and disposed of.
Documents to be reviewed are perhaps the most obvious example.
The key is that what you have to say isn’t buried in the
attachment. That’s in the email body that accompanies the attachment.
How big is too big?
One of the things I keep coming back to is the size implications of
attaching files to your email, particularly when used in lieu of alternatives
such as simply putting the message in the body and not using an attachment at
But it begs the question: if size matters, what are the rules?
Here’s where you get annoyed with me.
Or more completely, it depends on your recipients.
You know the old adage about writing: “Know your audience”? The same applies
here: know your recipients. Know what you can expect of them, know what’s
reasonable to “force” them to do, know what may, or may not be an issue for
If you don’t know, if you have to guess, then you probably want to assume
Let’s say you want to include a Word document as an attachment. Let’s also
say that document is around 800,000 bytes.
First, realize that because of the encoding used to attach something to
email, the attachment will actually be slightly larger than the original file
size. In this example I’ll say that the attached fill will be 1,000,000 bytes
Let’s start with your recipient’s download times:
Basic DSL, or roughly 658k bits per second (which is what
my 768k/128k DSL tested at some time ago) means the download will take about
15 seconds. Not too terribly unreasonable, I suppose.
Dial UP, commonly around 28k bits per second: the download
will take about 6 minutes. Suddenly things aren’t looking so
reasonable, are they?
Now, a lot of people argue that dial-up is dying, and that in most corporate
settings people are connected via broadband speeds anyway. My response? That
all may be true, but don’t assume it. Know it, or assume the worst. If
you assume that everyone can handle high speed you’re quite likely to
alienate the folks that you didn’t realize were still on dial-up. (And even in
professional settings, speed isn’t all it’s cracked up to be – just ask anyone
who travels and uses various WiFi hotspots or hotel connections.)
Let’s not forget disk space. You’ve just imposed a 1 megabyte disk space
penalty on your recipient in order to receive your email. Is that reasonable?
It might be. It might not be. If they archive their email, as many do, that’s a
permanent penalty. Is that reasonable? Is your message really worth
The fact is that the definition of “how much is too much” changes over time.
10 years ago one megabyte was huge, today it might not be. 10 years from now we
might all be shooting around multi-gigabyte high definition videos laughing at
“the old days” when a gigabyte downloads were measured in days, not
If you care about your recipients, if you want to maximize the chance that
your email is received and read, then simply do this: make your email as big as
it needs to be, and no bigger.
And since you probably still want numbers, I’ll throw out two:
I’d think twice about sending any email larger than about 200k.
There are ISPs and other mail systems that routinely block or discard emails
larger than 4 megabytes, though sometimes that can be as small as 1
As I said, those numbers change over time, but as of today if you do nothing
else, they’re reasonable rules of thumb.
So what are the alternatives?
There are two:
Put the content in the email body.
Put what would have been an attachment somewhere else.
The first is fairly obvious: for example rather than sending a word document
that contains your message, put the message in the body of your email and don’t
attach anything at all. Smaller, faster, more likely to get read. Everyone
That’s the preferred approach in general.
But sometimes, as we discussed earlier, text in the body isn’t the answer.
You actually need to share a file.
The second is only slightly more work, but will be very much
appreciated by your recipients, because it give them control. The technique:
upload your document or other attachment to a site that’s accessible to your
recipients, and then email a link to that document. Your email is short, to the
point, and quickly transmitted, downloaded and read. Then your recipient
gets to choose whether or not to download the document and when to do
The question that usually pops up is “ok, where do I upload that everyone
If you’re in a corporate environment, and all your recipients are in the
same environment, I’ll bet you have shared folders on your network that you can
simply copy files to.
If you or one or more of your recipients are just random internet users,
then it’s likely that your ISP allocated you some amount of space for a web
site. You don’t need to set up a web site, just upload your documents to that
space, and email out a URL to the people that need to see it. (In a corporate
environment you may already have web-visible locations for exactly this
purpose. If not, lobby for it.)
Use sharing or hosting services like Flickr or photobucket for images, and
other similar services for other types of content. Even discussion groups such
as Yahoo Groups include some amount of file sharing available to group members.
This is actually a rapidly evolving market, mixing on-line backup with on-line
content hosting, so the options here are growing and changing almost every
The other question I get about using any kind of accessible shared location
is security. What if you don’t want just anyone to see your document or
It’s typically very easy to password-protect such a location, and then share
the password with your recipients when you email the pointer to the document.
If you can’t password protect the document, then using a utility like WinZip
(or the free alternative 7-zip), create a password protected ZIP file that your
recipient can then download and unpack. The bonus is that zipping will also
compress the file and make for a faster download.
And for the extremely security conscious – yes, passwords as I’ve described
can be hacked by someone who’s very motivated to do so. If your documents are
that sensitive, though, then you shouldn’t be sending them around as
attachments anyway. Attachments are sent unencrypted, and anyone who can sniff
your email (as that motivated person might want to do) then has access. You’ll
need a more secure solution that’s beyond the scope of this article.
The whole point of sending out a message is to convey information; to get
that message read. Among other things that means you want to do what you can to
make it as easy on your recipient as possible. It’s not just about being nice
to them, it’s about increasing the effectiveness of your email; increasing the
chances that it’ll actually be read and acted on.
It works both ways. Not only do you want to get control of everything that’s
arriving in your inbox, but effective communication means you’re not feeding
the beast that is email in someone else’s inbox either.
Sometimes the beast turns around and bites back.