The paragraph that introduces the notion that not all things can be retrieved via the Web is slightly inaccurate.
The URI that supposedly identifies Johannes Vermeer actually identifies the page about Vermeer. Wikidata has the Concept URI to differentiate between the real-world object and the Wikidata page about that object, which for Vermeer is http://www.wikidata.org/entity/Q41264.
I would refrain from using "obviously" in the second sentence, because this is quite a big idea to grasp.
Since both the concept URI and the page URI are HTTP URIs, I think that "so-called HTTP URI" was intended to read "so-called Cool URIs". That is also an advanced topic. And creating an HTTP URI for a non-web resource doesn't automatically mean that you are (re)directed to a web resource that provides information about the non-web resource.
The Wikidata URIs in Exercise 2 refer to the pages, not the entities, although I don't think it matters too much at that point. If the URIs in the text are adjusted, they should be adjusted in the exercise too.
The paragraph that introduces the notion that not all things can be retrieved via the Web is slightly inaccurate. The URI that supposedly identifies Johannes Vermeer actually identifies the page about Vermeer. Wikidata has the Concept URI to differentiate between the real-world object and the Wikidata page about that object, which for Vermeer is
http://www.wikidata.org/entity/Q41264.https://github.com/unloch/lod/blob/a4337fb9b04f8b7683bbb63c1bbdb513cddfda18/_sources/notebooks/Module1.ipynb?short_path=12a1353#L117
I would refrain from using "obviously" in the second sentence, because this is quite a big idea to grasp. Since both the concept URI and the page URI are HTTP URIs, I think that "so-called HTTP URI" was intended to read "so-called Cool URIs". That is also an advanced topic. And creating an HTTP URI for a non-web resource doesn't automatically mean that you are (re)directed to a web resource that provides information about the non-web resource.
The Wikidata URIs in Exercise 2 refer to the pages, not the entities, although I don't think it matters too much at that point. If the URIs in the text are adjusted, they should be adjusted in the exercise too.