How to use LOD for practical purposes?

As a newcomer to LOD, I find using LOD very very very confusing and impractical. To be clear, I think that by now I understand the model pretty well; the theory behind it. My problem is that most *practical* uses of LOD have been a really bad experience, in particular when linking different data sources coming from different places. It's pretty easy to reason about a single graph, that is a consistent graph that was built in one piece, since everywhere around the graph the structure is usually fairly constant and predictable. But when I want to get information from two or more linked graphs... oh boy... they can be using different types, different ontologies for the same thing (or even custom ones!), different ways of linking, different conventions, ... As a human, I can more or less navigate through the graphs: I start somewhere and I follow the links, and I find something that makes sense to me. But I can't see a computer doing this kind of work; it's a hard problem that has got to require some kind of intelligence.
So my question really is: what am I, the user, supposed to do to get information out of linked graphs? I download 2, 3, o 4 graphs from various sources, then what? Am I supposed to make my own graph by inferring/reasoning/extracting data from those sources in order to make them more reasonable? In a perfect world all those graphs would be all perfectly linked and plug-and-play but this clearly is not how people publish their data. Or is there a magical way to make all this information *practical* to use, something that a computer can use without requiring an ultimate AI?

Received on Monday, 19 November 2018 10:29:12 UTC