------The introdution about'Valve'
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Valve's portfolio of entertainment titles also includes Half-Life® 2, Counter-Strike®, Day of Defeat®, Team Fortress®, and Portal™. This portfolio of titles accounts for over 20 million retail units sold worldwide, and Valve games account for over 80% of the PC online action market.
In addition to producing best selling entertainment titles, Valve is a developer of leading-edge technologies including the Source® game engine and Steam®, a leading platform for digital content with over 10 million registered users.
Today, Valve is composed of just over 120 of the industry's best artists, programmers, and writers. In the company's 10-year history, it has risen from "unlikely new entry" to industry leader, producing a string of best selling and critically acclaimed PC products and technologies.