People believe a lot of strange things in this world. They worry specifically that SharePoint won't perform as well as they need, and that they can write some sort of ASP.NET app with a SQL backend that will somehow outperform it. I really liked this post from Eric Shupps that lists a few of them. Keep in mind these are all myths - that is "not true".
Eric goes into quite a bit of detail debunking each of these 5 myths, so if you have a tendency to believe these things, here's a chance to get straightened out on that.
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