You've probably heard terms like...
There are subtle differences...
but basically these are just different names for the same meme
actually most people involved seem to prefer the term Linked Data

the musical genre modal jazz has the URI:
<http://dbpedia.org/resource/Modal_jazz>
and the music artist Bill Evans has the URI:
<http://dbpedia.org/resource/Bill_Evans>
and the property has genre has the URI:
<http://dbpedia.org/ontology/genre>
We can use RDF to say "Bill Evans' musical genre is modal jazz"
<http://dbpedia.org/resource/Bill_Evans>
<http://dbpedia.org/ontology/genre>
<http://dbpedia.org/resource/Modal_jazz> .
Music hack day, London
The MusicBore the grand-prize-winning hack used the Web of Linked Data!
Watch the screencast (warning: lots of IRC geekery)
and now...