That's right, files might be named shtml. Hadn't thought about that. But if the file isn't an index, that detail makes it to the client side, confusing users, doesn't it?

The phrase "server side includes" doesn't appear anywhere in the "#include" directive. I'm talking about what could be gleaned from the code alone. And again, if they put file or virtual in their search term, they get the result. I just don't expect all web developers to do that.

To address your last point: the #include language seems simple but it doesn't explain why it's happening. It would seem like black magic to someone who thought their host was just sending files to the client and didn't know about SSI.