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If you are managing data that you intend to distribute/share/transfer to other parties, it is good to adhere to the rule that all resources are given HTTP URI names from a namespace (domain or IP address) that a) you control and b) are resolved to something meaningful.
There is an exception though: if all the information is a) managed in a siloed environment and b) can be represented explicitly as linked data requiring no resolving, you can freely use any URIs you wish without worrying about them resolving to anything nor conflicting with existing URIs outside your environment. This means that you can also mint URIs for resources before you have a framework ready for resolving them.
Linked Data is Atomic
It is crucial to understand that by nature, linked data is atomic and always in the form of a graph. The lingua franca of linked data is RDF (Resource Description Framework), which allows for a very intuitive and natural way of representing information. In RDF everything is expressed as triples (3-tuples): statements consisting of three components (resources). You can think of triples as simply rows of data in a three column data structure: the first column represents the subject resource (from whose point of view the statement is made), the second column represents the context resource of what is being stated by the subject, and the third column represents the object or value resource of the statement. Simplified to the extreme, "Finland is a country" is a statement in this form:
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