The articel does not mention what he did, so here it is:
<a href="http://en.wikipedia.org/wiki/Erik_Meijer_%28computer_scientist%29" rel="nofollow">http://en.wikipedia.org/wiki/Erik_Meijer_%28computer_scienti...</a><p>"His work at Microsoft included C#, Visual Basic, LINQ, Volta, and the Reactive programming framework (Reactive Extensions) for .NET"