One of the ways that web applications won over desktop application is the power of URIs.
With a URI and objects accessible on the web, I can get access to an article, but also an email, a calendar event, etc.
With desktop apps, if I want to "link to an email" it's virtually impossible outside of very specific application like Emacs that allow interlinking.
I feel like we're close to seeing this solved, but until then, the web has a hug advantage.