Great snippet from Eric van der Vlist on XML-DEV:

"RDF and its triples is really lightweight when you have the right tools to manipulate them. I like to think of them as a RDBMS with a variable geometry: each "row" (ie each subject) can have a variable number of columns (properties). It's like a RDBMS which you could populate before having written any schema, that's really very flexible and it's just a matter of using the right tool. When I use such a tool, I have a feeling of RDBMS without its straitjacket :-) ..."Link