History
In the beginning, (well, 1980 or so), people talked to computers through terminals on serial lines. There were hundreds of brands of terminals, but in the early-'80s the VT100 terminal from Digital Equipment Corp. quickly found favor and fast became an industry standard.
Like all terminals of the time, it displayed 24 lines of characters, with 80 characters max per line. There were no proportional fonts on computer terminals, so every character took one space. A line of 20 "i's" was the same length on screen as a line of 20 "M's".
Because of this history, the 80-character line became the defacto standard for terminal devices. Such "dumb terminals" are still widely used on various systems throughout the Internet. The implication for email is this: since you don't know what kind of device your reader will be using, you should assume the "lowest common denominator" of an 80-column fixed pitch display.
If you send lines of characters which are longer than 80 characters, but your reader's display is set for 80 characters, your reader's display will either truncate and show only the first 80, or it will wrap all the words beyond 80 characters onto the next line.
The result is that your reader will see a display like this paragraph,
where I've forced
a display similar to what readers see when lines are too long. Because there
were a few too
many characters on each line, the reader's mail program forces the extra
words from each
long line down onto the next line, creating shortened lines in between the
actual lines and
making the entire paragraph very hard to read.
If you've written indented paragraphs like this one, then the
long
lines still get wrapped to the next line, and your paragraph will
look
something like this!
Word wrap
This leads to the related subject of word wrap. As you are typing
messages into your computer, you may or may not hit the Enter key
at the end of each line. When you hit the Enter key at the end of
a line, you are in effect saying "the end of this line is HERE.
Go to the next line."
That's what I did on the paragraph above. On the other hand, if you don't hit Enter but instead just type and type, your software will generally "word wrap" what you type. That is, as your cursor reaches the right edge of the screen, it will jump down to the next line automatically, without requiring you to hit Enter. That's what I've done in this paragraph.
The "problem" with this is that your text now does not contain any specific "end of line" markers. The paragraph is stored and sent as just one very long sentence. If your reader's software *also* has word wrap, you are in luck, because it will wrap your sentence/paragraph to fit whatever size window your reader is using. If you will widen your browser window right now, you'll see that the paragraph above also widens to fit the window, while the lines in the paragraph above do not.
If everyone had software that supported word wrap, then you could safely create entire paragraphs without hitting Enter and let each reader's software wrap the lines to fit their choice of window size. But some readers *don't* have word wrap, and your long lines will be unreadable to them.
So, the bottom line:
We recommend that you create your email messages with a hard "Enter" end-of-line at the end of each line, and that you make sure that none of your lines exceed 76 characters. The easiest way to do this is to use a true editor (not a word processor) such as Ultraedit. You can download Ultraedit from http://www.ultraedit.com. It's well worth the small registration fee, but there are also similar free editors or you can even just use Notepad.
We recommend 76 instead of 80 because frequently email messages are quoted in reply, with ">" or ":" added to the beginning of each line. If your message is quoted and the lines were 79 or 80 characters, the quoting makes them 80 or 81 and the problems above start to appear.
But wait, we're not quite done.
Proportional fonts
These two lines are displayed in a fixed-pitch font:
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
These two lines are displayed in a proportional-pitch font:
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
On each line, there are exactly 50 characters.
Most email programs use proportional fonts by default. True, they look a little better to *you*, and they look fine when received by someone else on the same service with the same software and the same screen size.
But when you start sending messages to others on the Internet who are using different software, or simply larger monitors, your message may look very different.
Take a simple table, for example, which was created with a fixed-pitch font:
Pricelist --------- 1 to 9 items (price each) ..................... 50.00 10 to 99 items (price each) ...................... 5.00 Over 100 items (price each) ....................... .50
Which is then received and viewed with a proportional font:
Pricelist
---------
1 to 9 items (price each) ..................... 50.00
10 to 99 items (price each) ...................... 5.00
Over 100 items (price each) ....................... .50
With fixed-pitch fonts, all the prices line up directly above each other.
With a proportional-spaced font, each line is a different length.
If you create such a table in your email program, with a proportional- spaced font, it looks great on your screen. But send it to any of the thousands of readers who have their email readers configured for fixed-space fonts or even just a different proportional font, and your carefully-crafted table will be very hard to read.
If your email program won't allow you to change fonts, then use a different editor or even a word processor (e.g., Windows Notepad or Windows Write respectively) which will allow you to change the font. Select a fixed-pitch font to construct your message, then when it's all finished, save it into a file for future reference, then cut-and-paste the entire message.
Here is a 76-character line:
1234567890123456789012345678901234567890123456789012345678901234567890123456
If you use a fixed-pitch font, you can use this line as a "ruler" when you prepare your messages, to make sure all the lines you create are shorter. If you use MSWindows notepad, you can:
1) Start notepad.
2) Click Format and UN-check WordWrap.
2) Click View and select Status Bar.
3) Now as you type you can see the exact length of the current line on the status bar. Do not let any line exceed 76 characters before you press Enter.
Summary
Remember that not everyone views electronic messages in the same way you do. PC's or Macs, 14" monitors or 20" monitors, 640x480 or 1024x768, fixed or proportional, 8pt or 12 pt, size of the viewing window - all these make a difference. But if you follow the guidelines given here, your message will look good to almost everyone who reads it.