Yes, one could do that with Acrobat. But not everyone owns Acrobat and with Acrobat it is slow, cumbersome, and no fun. With Jump it is still no fun – but at least it is simple and fast.
What is what – you ask? Well, creating “jump to” links/marks (annotations) within an exciting PDF document. Sometimes one is in the need of doing that and with Jump you can just do exactly that; nothing else.