What is the best way to launch a product and create traction? There are many approaches, but I think it’s most helpful to start with a simple metaphor: you need to drive a wedge. In fact, nearly everything that is successful can be seen as having started by driving a wedge.
Wedges are crazy powerful tools. Wikipedia calls them one of the most important inventions in human history. The idea behind wedges led to the ramps that enabled the construction of the pyramids, and wedges are at the heart of the plow, which enabled agriculture.
I looked up a few definitions. Here’s one:
Wedge, a device tapering to a thin edge or point, and used to split or pierce objects.
And another one:
A wedge is a simple machine that increases force by reducing the area.
If you combine these two definitions, you arrive at the central principle: you can increase force — thereby enabling you to pierce or split an object—simply by reducing the area to which that force is applied.
The application to business is clear: You need to find a point — just one point — to enter whatever market you’re in. Facebook did it at Harvard. Yelp did it with a core group of fanatics in San Francisco. Then they expanded.
Don’t be afraid that if you start too narrow, you won’t succeed! I think we are all at risk of ignoring the power of a wedge strategy because we tend to look at successful companies as they exist today and not as they started. You might look at Amazon.com today and marvel at the breadth of their business. But everything that is successful starts with insane focus.
Any time you feel the tug to broaden the scope of what you’re creating, remember: Everything that is big starts small. Obama didn’t start out as president. He was a community organizer first, then a state senator, then a senator, then president. Amazon was an online bookseller first. Then a book, DVD and CD retailer. Then an everything-retailer. You just need to find the courage to reject distractions and focus your offering.
 Paul Graham discuss this idea in terms of targeting a very specific set of potential users to pierce barriers in a market: http://paulgraham.com/ds.html. As I mentioned in a previous post, I think driving a wedge should not only inform the market you target but also how you build your product. Even if you target a small set of people, if your product tries to do everything, it will flop. You need focus in your product as well as your market.