We expect everything to be nearly instantaneous nowadays - our meals are ready in under three minutes, thanks to the drive-thru's and microwaves; even our favorite television programs can be seen without commercial breaks, thanks to TiVo and DVR. So, it is no surprise that e-mail - which is the fastest and easiest form of interaction today - is the number one means of communication in the business world. 
As we rely more and more on e-mail as our main form of communication, keep these three things in mind:
1. Unlike many other forms of communication, like the telephone and the simple face-to-face interaction, e-mails are actually legal documents. Yes, e-mails are admissible evidence in any kind of court case where the content of the document is proven to be relevant. E-mail has even played a large role in the current Peanut Corporation Salmonella Incident.
2. Choose your words carefully. Be cautious of what you write in an e-mail to a vendor, employee, prospect or customer. Take this scenario for example: A vendor e-mails you an estimate and you reply back, "Sounds good". To your vendor, this response could be perceived as approval to proceed with the project, when all you meant was that the price seemed fair. Needless to say, how you say what you say in an e-mail is of utmost importance. Check out Robert Scobel’s popular tech blog and see what happened to him through a personal e-mail he sent to a company in regards to a speaking engagement. This could happen to YOU.
3. E-mail is a one-way form of communication. As "marketing and PR people", we are the in the business of writing and choosing our words carefully. But, the fact is that, at times, we are all victims of our own words. It is important that we remind ourselves, and each other, that e-mails are all too often one-dimensional because you never know how the person on the receiving end is going to interpret its contents.
To avoid eating your words later, next time you write an e-mail, consider its contents before you hit send. Or, instead, you could just pick up the phone.