> They say things like auctions, but I don't see what's wrong with SQL for those.
For local data sets, SQL's great. For remote, centralized data sets you can use something similar.
But once you want to combine data sets spread out over several sites (say, combining IMDB with local movie listings) you need to express that data in a format with globally unique identifiers and distributed extensibility. That's RDF. You can still have a nice query language, see SPARQL (which is much nicer than SQL, IMO).
> And if you used Google to search the web for millions of currently-listed auctions on webpages in XML format, you'd have a difficult time trying to find what you want.
Sure, if you're just doing full-text search like Google does. Of course, the point of having machine-readable data is that you're not limited to full-text search.
For local data sets, SQL's great. For remote, centralized data sets you can use something similar.
But once you want to combine data sets spread out over several sites (say, combining IMDB with local movie listings) you need to express that data in a format with globally unique identifiers and distributed extensibility. That's RDF. You can still have a nice query language, see SPARQL (which is much nicer than SQL, IMO).
> And if you used Google to search the web for millions of currently-listed auctions on webpages in XML format, you'd have a difficult time trying to find what you want.
Sure, if you're just doing full-text search like Google does. Of course, the point of having machine-readable data is that you're not limited to full-text search.