I sometimes use Wikipedia to fill in gaps in my historical understanding of genres or the interrelationships between bands/producers/studios/genres/etc. Because so much of the value of Wikipedia is in the links and lists of links (almost moreso than the actual content in the page), I find my exploration is less predetermined by simple popularity/centrality of a particular page or cluster of pages. And yet... you're still stuck in someone else's garden, and you won't find many local/rare materials. For the rarer stuff, I have used similar methods on discogs.
