One of the most recognizable semi truck features are the vertical exhaust stacks. Other than looking cool, they also carry a ...

Instead of returning thousands of links from a query, as is common on a general-purpose search engine such as Google and Yahoo!, vertical search engines deliver more relevant results to the user.

That journey toward vertical integration ... is), more like buying a passenger car. You have a pick of a few packages, with major components such as engines and transmissions made by the OE.