About: http://webisa.webdatacommons.org/48900168

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	If rough estimates are enough, than my solution is a good start (it certainly could use some more work, and support for IE which should be lot easier in this case as the TextRange object actually gives offsets in pixels).
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com