Different people have different learning styles, and different methods are more effective for some than for others.
I'm +1 on RTFM, but I'm a professional technical writer, and I
like having a job.
I know manuals. I make them all day long. I know how they're structured, how they're built, why they can go so horribly wrong, and I even know the black magic of how indices are made, so I can look things up in them, demented as they typically are. When I get a new camera, I read the entire manual from cover to cover, just out of professional curiosity. I doubt this is the best way for everyone to learn their camera; it's just how
I do it.
Some folks learn by reading. For us, the manual and website thang is good. Some folks learn by hearing or seeing something. For them, podcasts, youtube and classes or a mentor are going to be the best path. Other folks gotta learn by doing. Most of us use combinations of all of the above in varying amounts.
But I would never assume that what works for me is what works for everyone else.