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

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.