Yahoo used a stripped down and customised version of Symfony (called ysymfony). As far as I recall they stripped out the Model part of symfony - so the entire P

Yahoo used a stripped down and customised version of Symfony (called ysymfony). As far as I recall they stripped out the Model part of symfony - so the entire Propel/Doctrine stuff. Answers for example, wrote their own data query/persistence. So although you mention doctrine:migrate - Yahoo were not using it on Answers, and if Delicious, Bookmarks and Daily Motion were using the Yahoo version of symfony, neither were they.