"Beware the exclusive," warns longtime tech industry commentator Dave Winer. He says companies that give their announcements to one and only one publication, in exchange for a big splash, risk their eggs in one basket. Readers, too, should beware the exclusive. If a publisher has a piece of information he's sure no one else does, it's tempting to play it as big news to flaunt against competitors. One of the most important functions any writer can perform — whether NYT editor or small-time blogger — is to filter what I know that you don't down to what actually matters. This week's Web 2.0 Summit will produce plenty of "exclusives," few of which you'll truly need to read.