More or less, there is no Flickr pro because Marissa Mayer believes there are no professional photographers. I'm sure this rubs a few the wrong way, rightfully so. I disagree with her, but I have always believed that the second some people bought a dSLR, they automatically thought they were professionals ready for action and are sadly mistaken. I do fully disagree with her assessment that just because pro cameras are readily accessible, that there aren't any true professionals specifically on Flickr.
[source: http://rising.blackstar.com/yahoo-ceo-marissa-mayer-is-making-no-friends-in-pro-photography.html]
[source: http://rising.blackstar.com/yahoo-ceo-marissa-mayer-is-making-no-friends-in-pro-photography.html]
“There’s no such thing as Flickr pro because today, with cameras as pervasive as they are, there’s no such thing, really, as professional photographers. And then there’s everything that is professional photographers – certainly there’s varying levels of skill – but we didn’t want to have a Flickr pro because we wanted everyone to have professional quality photo space and sharing.”