You probably receive dozens of email messages every day. Most of them are likely spam. And you may send as many as you receive. Could the email you send also be regarded as spam, or worse?

The ease with which messages can be sent and the low cost make email a powerful tool for business. It also makes it easy to abuse.

It used to take time to put pen to paper, address and seal an envelope, and walk it to the post office, or at least to the company mail room. But that delay gave us time to reflect on our words. It gave us time to count to ten and take a deep breath before responding to some perceived provocation in the heat of anger. And the cost, even if it was just a few cents, made it that much less likely we'd waste our time and money sending something nonsensical.

Email has changed all of that.

Now, in a few seconds - the time it takes for a couple of mouse clicks - we can forward to all our friends the inane drivel our friends send to us. Or, if someone sends us a nastygram, we can respond in turn, quickly, while we're still riled and before we have a chance to calm down. And the hectic pace at which we're all forced to work makes niceties like spelling and grammar seem superfluous.

Unless we're careful, this speed and convenience can come at a cost; poorly written email can hinder your career advancement. Paul Siddle, Principal of The Executive Protocol Group, a firm specializing in business etiquette training, notes the potential damage to one's professional prospects when email is misused: "If the employee's email contains misspellings, IM abbreviations, and a general lack of continuity, his or her ability to communicate with all levels of management and clients may be questioned."

Given the power of email - and the human propensity for making fools of ourselves - it pays to keep in mind some basic points of email etiquette.

Nothing spells unprofessional like poor spelling, and with just about every email client available equipped with an adequate spell checking program, there's no excuse for it. But don't depend on your spell checker to catch every mistake, including words that are spelled correctly but used incorrectly. Become familiar with commonly misapplied words, like then and than; their and there and they're; two, to, and too.

Correct spelling also means avoiding the shorthand popularized by instant messaging and chat users, like gr8 instead of great, and u and r instead of you and are.

Using all capital letters makes it seem like you're SHOUTING. Unless you mean to shout (and why would you in an e-mail message?) use correct case.

Keep your paragraphs short. Large blocks of text are difficult to read on screen. Paragraphs should be 3 to 4 sentences long.

Use "reply-to-all" intelligently. If the original message was simply a general notification to a group, it's likely most of the recipients don't need to see your reply. At the same time, be careful not to exclude people who do need to be kept in the loop.

Use descriptive subject lines. Messages with subject lines like "Hi!" and "check this out" may be marked as spam by mail gateways and be deleted before your recipient ever sees them. One professional who works out of his home almost deleted a message from a client, assuming it was pornographic spam, when she used a subject line that read "I called your home and your wife answered."

Do not reply in anger. Remember that intentions are not always clearly communicated in email. What you think is an insult or criticism may simply be an attempt at humor. Even if some insult was intended, you accomplish nothing positive by replying in kind, and may only hurt yourself. Email messages can be filed away and kept for a long time and may come back to haunt you later. Instead, calm down, think rationally, and if it's still necessary to have your say, do so in person if at all possible.

On a technical note, be considerate when sending attachments. Large files can bog down email systems. Some file formats, like Microsoft Word and Excel, can carry macro viruses that may damage the recipient's computer. Because of the inherent dangers, some e-mail systems strip all incoming attachments. It's wise to ask before you send anything.

Once you've composed your message, review it before you hit Send. Read it slowly; you may be surprised at the mistakes you find. If you're dealing with a sensitive subject, read it again.

Above all, learn when to avoid email completely. Face-to-face meetings are still the most effective and personal means of communication; we naturally convey much of our message by facial expressions and body language. Phone calls rank second, allowing our tone of voice to clarify our meaning. Paul Siddle observes, "Email does not provide this and often, attempts at humor, particularly sarcasm, are misinterpreted."