In addition to what was said above, it may be worth noting that you can put DT item links almost anywhere that will accept a link. So I link to projects or documents from inside my task manager (2Do app) and my calendar (Fantastical). They can also go in the notes in Contacts, and I also put them in mind maps made with iThoughts.
If that sort of thing is useful to you, you might want to take a look at Hookmark, too.