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I've been running Simpy for almost 4 years now. Every once in a while I get the "Why should I use Simpy?", "Why is Simpy better than, say, del.icio.us?" This post answers those questions in the form of "Why I use Simpy" answer. This are my personal reasons for using Simpy, but you can also read other people's opinions. I also encourage you to add your reasons in the comments, so I can add your reasons to this list.