Looks like it's switching around depending on what backend their load balancer throws you to. It's jumping around for me, which suggests they don't have any session affinity. Interesting, but I guess it's not required for their kind of app.
Just as most new web sites are not startup companies, most existing web sites are not apps.
The distinction and difference is that a software application helps a user perform manipulation or transformation of data as useful work.
Most websites, despite simple interactivity (e.g. search), are still published as "content" for consumption within a content access application, not for manipulating work|play|creative output.