Originally Posted by
sleepyphoenixx
I'm pretty sure BoED is the only place that says so. At least i don't know of any other rule that explicitly tells us that feats are (Ex).
And it's not all feats. Reserve, Psionic and Exalted feats are (Su) and Domain feats are SLA's iirc.
But yes, assuming that feats are (Ex) unless specified otherwise would make them special qualities, since every special ability that's not an attack is a special quality by default..