1) The document discusses RDFa, which bridges the gap between the Web of Documents and the Web of Data (Web 3.0) by embedding RDF triples inside XHTML pages.
2) An example shows how to annotate HTML with RDFa by adding attributes to designate namespaces, types of entities (people), and properties (name, nickname, affiliation).
3) Nesting is used to include one entity (address) within another (person), with the relationship indicated by the "rel" attribute. A graph is drawn to represent the RDF data.