Structured data is often available in XML or JSON formats on the Web. The high popularity of these two formats is due to the fact that both are human-readable, easy to handle from a programmatic point of view, and can manage any type of hierarchical data structure, not just a simple tabular design, as CSV files are.
Note
JSON is originally derived from JavaScript Object Notation, which recently became one of the top, most-used standards for human-readable data exchange format. JSON is considered to be a low-overhead alternative to XML with attribute-value pairs, although it also supports a wide variety of object types such as number, string, boolean, ordered lists, and associative arrays. JSON is highly used in Web applications, services, and APIs.
Of course, R also supports loading (and saving) data in JSON. Let's demonstrate that by fetching some data from the previous example via the Socrata API (more on that later in the R packages to interact with data...