Sean notes that there are lots of triples in spreadsheets. Yup. After my Aug 2003 trip to Montreal for Extreme, I used gnumeric as an RDF authoring tool to collect all the gas receipts and such; then the Makefile has this stanza to convert it to RDF:
triplog.rdf: triplog.xml grokSheet.xsl $(XSLTPROC) --novalid grokSheet.xsl triplog.xml >$@
I haven't scrubbed the data, so this is somewhat incomplete as a demo.
Yes, this is another GRDDL style transformation.
A comment on Sean's blog said "don't forget RDBs". Of course not. See Relational Databases and the Semantic Web; I hope to update my implementation, dbview.py to use SPARQL before too much longer.
Hmm... where are timbl's slides on RDF, trees, tables, and such?