I've been using reader for /years/ now, and I still don't think I know all its features: I just found out yesterday - completely by accident - that pressing 'f'

I've been using reader for /years/ now, and I still don't think I know all its features: I just found out yesterday - completely by accident - that pressing 'f' throws reader into a really simple river-of-posts mode with all the headers and navigation widgets hidden. I hope the change will make these kinds of features more prominent (but to be honest, I really doubt this will be anything but dumbing it down)