Use Twitter to gather intelligence about your target clients and to announce your products and services:
Start a Twitter profile. Visit Twitter.com and sign up. If you want to communicate with just a few clients or colleagues, keep your stream private by checking the "protect my updates" box under Settings.
Spread the word to your target audience, with simple instructions on how to sign up for a free account and follow your stream. Now you're rolling.
Explore the universe. Share news from seminars and other events; broadcast meetings and meeting places; announce your teleclasses; open a video or audio channel for those who can't join you.