Best of all--it's all free. Facebook may be built for and targeted at individual users, but it is also a valuable platform for business marketing and communications, except for one thing: e-mail. Adding e-mail to the mix would provide the final piece of the puzzle and make Facebook not just the biggest social network, but a comprehensive, and formidable business tool.

Google--which is vigorously trying to break out of its own mold and establish a presence as a business communications and productivity platform as well--should be on notice. While Google tries to challenge Microsoft head to head in the messaging and office productivity fronts, and struggles to get into the social networking game, Facebook is outflanking it.