1. To allow visitors to quickly identify your purpose. (Don't waste their time.)

2. To avoid others from sending you messages that have nothing to do with your purpose. (Don't let them waste your time.)

If you are using a social networking site as a method of promotion for a business opportunity, or other program, say so, right up front. Don't beat around the bush about it.

Your mission statement should be about what you are promoting, but not an advertisement for it. That is to say, use your own words to describe your business, not some pre-written gobbledegook, that someone you don't know wrote. People respond better to sincerity than hype.

Write about the company history, why you became involved, and what you like best about it. If you are promoting a program, or product, tell about what sort of results you've had with it, and how it has personally helped you. Not how much money you've made, or how much someone else could make.

When you write about yourself, be honest. Tell your visitors who you are, not what you're wanting them to buy. If you live in nowhereville, say so. If you've got ten kids, talk about it. Tell about your education, your experiences and accomplishments. Let your visitors know you are a real person. Include your photograph. Not a picture of a product, or cartoon character, but a picture of you.

Don't fill your profile with banner ads. This is obnoxious to the visitor, causes the page to load slower and visitors to leave frustrated. The same applies to flash and video. It may look cool, but those things make page load time drag on forever, especially for those using dial up. Most people won't wait more than a couple of seconds for it to load, and will leave your page before you want them to.

Likewise, don't go crazy with fancy fonts and wild color schemes. You may have perfect vision, but not everyone else does. Use color with care. Keep your visitor in mind, not your own personal preferences. If they can't read your profile page, they will leave it. I've got good eyes, but I'll leave a site that is too busy, or has a loud color scheme. It is distracting, not attracting. If I have to strain to read it, I leave it.

Use solid colors for the background, rather than images. Again, images are distracting, and make the text difficult to read. If they can't read the text, there is no purpose for staying.

If you are using audio, make sure that your visitor has the option of turning it off. Some people just don't want to listen to it.

Finally, as a visitor to someone else's social networking site, don't fill their comment boxes with images, banners, or other wise. It is tacky and rude. It distracts other visitors from the profile's purpose. No matter your intention behind posting an image, it is an unfriendly thing to do. It's like jumping up and down, yelling, look at me, not them!