There are not many really useful business tools that can lay claim to being 100% free. Twitter does, however, and while the opportunities it presents aren't really obvious at first glance, they're still manifold. Business users are learning new ways to turn Twitter to their advantage each and every day. Surprisingly, one of the best uses of Twitter is to add some human personality to you, your brand, and your company. One of the worst uses? Posting links to your own websites, day after day after day. I - Introduction to Twitter II - How Business Has Embraced Twitter III - Social Strategies IV...