First of all, sorry for the bad terminology used here. I have no clues on what the thing I try to explain is called. Let me try:

I recently see a lot of nice websites being build with a "seamless hyperlink" system -- when hyperlinks are clicked it does not visit a URL but it somehow switches to it seamlessly (no page reloading or such). Some websites do this in such a good way that it looks like the Adobe experience manager training website is done as a single piece such as the flash websites of the early 2000s.

I'm aware of this topic:

Here is an example to explain what I mean: http://www.thenerodesign.com/

I'm aware of this thread: How does GitHub change the URL without reloading a page?

What I'm asking here is not only the "change of the URL" part ut also "loading of the clicked content" part. I can modify the address bar, no problems with that. However, I have no clues on how to display different websites when a certain URL is visited, or how to load a clicked hyperlink in a seamless way like the website example above.

Therefore, the question exceeds the "history API"