About: http://webisa.webdatacommons.org/250435011

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	It can search by all the criteria listed except perhaps attachments (it does tag messages with attachments, but I am not sure what types of searches the submitter wants to do with them).
http://www.w3.org/ns/prov#wasQuotedFrom	slashdot.org