What would you hold up as an example of a
    powerful web app with significant usage?

The web as a whole is one gigantic web app that works wonderfully. I am using the web all day and for pretty much everything. HN and the linked articles for news. Trello, Github, Upwork for collaboration. FB and Meetup to find an save events I want to attend. Booking.com to find and book hotels. My local railway site for train travel. My local cab site for cab rides. My local public transport site for bus/subway rides. Google flights for flight planning.... I could continue forever. Whenever I need something, I find it on Google and just use it.

"All the major players these days (like Facebook) get the overwhelming majority of their traffic through their native mobile app"

Source?

And I do not think, there is a sharp line between WebApp and Website. You could say, we are using one right now (even though very primitive) discussing right now - more than "static(-ish) content"

Also most of the other parts of the Web are not really static anymore - highly dynamic, live interaction between the whole world! That's pretty awesome if you think about it. So the Web works and the web is faaaar away from static documents linking each other, what was it's origin.

And with real webapps - well, I believe the big ones are about to come. The underlying technology to really make them usefull, is just about to become stable.

I think the fact that most facebook users only access it trough mobile is because of the general shift to mobile. Even most web usage is now on mobile: example source: http://www.telegraph.co.uk/technology/2016/11/01/mobile-web-...

> What would you hold up as an example of a powerful web app with significant usage?

Google Docs suite perhaps?