Viral Loop

Here's something you may not know about today's Internet. Simply by designing your product the right way, you can build a flourishing business from scratch. No advertising or marketing budget, no need for a sales force, and venture capitalists will flock to throw money at you.Many of the most successful Web 2.0 companies, including MySpace, YouTube, eBay, and rising stars like Twitter and Flickr, are prime examples of what journalist Adam L. Penenberg calls a "viral loop"-to use it, you have to spread it. After all, what's the sense of being on Facebook if none of your friends are? The…