As mentioned in the comments of the article: What part of the lost traffic is people figuring out they can search Wikipedia directly?

I've noticed older people are more likely to search Google for Youtube videos than they are to search Youtube. Same goes for trying to search other sites, they'll search for something and include "wikipedia" in the query.

The younger ones I've noticed (really small sample size of "my siblings and their friends") actually search on Wikipedia or Youtube.

Until I started using keywords to search sites directly, I was guilty of the former method myself.