The Magic Quadrant is a graph comprised of two axes: one for completeness of vision and the other for the ability to execute. The graph is divided into the following four quadrants (clockwise starting from top left): challengers, leaders, visionaries, and niche players.

Niche Players: Sneaking into the Market
Those who score low on the completeness of vision scale and low on the ability to execute are called Niche Players. They only provide part of the whole picture and must integrate with other vendors to provide the entire solution. They are trying to enter the market by trading on one (niche) expertise and may spend limited effort on software development and marketing for this particular market, because their focus lies elsewhere.

Leaders and Challengers: Deep Pockets
The ability to execute indicates marketing prowess as well as the ability to support their sales. Those who score high on the ability to execute are called Leaders and Challengers. They are often well-established names with existing software and customer base. The challengers are just as big as the leaders, but have a slight different core focus, and therefore, an less complete vision in the given market. From a technological point-of-view, because leaders and challengers already have existing software, they will try to integrate their existing product offerings into the given market and will end up with less generic solutions, with vendor lock-in as a likely result.

Visionaries: Focus on Technology
Visionaries on the other hand are motivated to be generic, working on open source as well as proprietary platforms. They score high on the completeness of vision, but low on the ability to execute. They are the ones who approach the given market with a fresh perspective, often designing from scratch. Technologically, they are the most advanced and innovative, with cleaner solutions. However, they may lose to the leaders because of limited marketing abilities and sales support.

Gartner has published many market research documents that includes the Magic Quadrant, some of which are available on the internet.