John Mueller from Google replied to a question in the Stack Exchange forums about following up YouTube set up their structure and how it might impact them if they followed, from an SEO crawlability perspective.

John responded that it is often not a good idea to just blindly follow how big sites do things because they often get it wrong, he said.

The question was:

John replied:

YouTube, a Google owned property, do something wrong? No way!.

In any event, John went in and explained what he should think about in detail in the thread.

Forum discussion at Stack Exchange.