You mean top companies like, say, Facebook? Or startups like, Esper? I'm not really sure what your comment is trying to say because it comes across as circular

You mean top companies like, say, Facebook? Or startups like, Esper? I'm not really sure what your comment is trying to say because it comes across as circular ('they're popular because lots of people use them'). Edit: seems you've added the links I was about to point to.