[@ashfame Participant 15 years, 11 months ago]

Yes you are right about the deep integration.

Matching themes this way is a solution but it comes with a performance penalty but its economical at initial stages.

In that guide, since WordPress is loaded too.

Instead of calling bbPress header file, we call the WordPress header file so as to bring the code from there. Same goes with the sidebar and footer.

That’s how forums are housed inside WordPress theme.