It's hard to take the question seriously, given that Google, Travelocity, etc. care deeply about their businesses, and entrust them to open-source databases. And yet the question still comes up, as it did at eWeek recently.
eWeek asked Kevin Closson, chief software architect for PolyServe-HP, who answered 'Yes,' open-source databases (like MySQL and Postgres) are serious alternatives to Oracle et al, but that it depends on the application:
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