XNA Content Pipeline Question

Hi, i'm taking a course on game development, and unfortunately we have to use M$ C# and XNA.
Although its M$, i must admit that both C# and XNA are pretty cool ;)

Can someone tell me if i got these points right?

The Content Pipeline can ONLY be used on "assets" (whatever this term exactly means) that are PART of the project.

So if i added a my.bmp to the project and set "XNA Framwork Content" to true, i can do a ContentManager.Load("my.bmp");

But if i didnt add the file to the project its not XNA Content, and so there is no way i could load a file using the ContentManager then.

So content is pretty much static - in the sense that once the project is compiled, noone could ever modify the contained content again (without hacking).

So if i want my project to be extensible e.g. by allowing adding custom meshes, sprite animations, fonts (just a texture plus some meta data where the chars are) then i better not use it as content, but use files instead and handle the loading myself.

If i wanted my project to run on the xbox, i'd be forced to add all files as content.

Is this correct so far? Thx for any responses :)