Flickr Pro means that you can take all the photos you like with all your phones, cameras, celluloid lightboxes, microwave ovens, etc. and store your memories all together in one place for $24.95 per year.
I had a subscription to Flickr Pro once, but for the amount of photos I took I didn’t think it was worth the $24.95.
What peeved me the most about it is they take the Quicktime Pro model of upgrading. For regular users, Flickr only shows the most recent 200 photos. If you want to go beyond that (say, after years and years of taking photos you might actually want to see early ones) you need to upgrade and get all the features you might not care much about, just like how if you wanted full-screen Quicktime viewing you had to buy a Quicktime Pro license.
Once of the things I hope Flickr clears up in 2012 is to let me know who this site is for. Is it for hard-core and/or professional photographers, or is it for regular joes to post photos to? And for both of those groups there needs to be a compelling reason why you would use Flickr over the other alternatives (photography CMSs, Facebook, Instagram, whatever). “View more than the latest 200 photos” isn’t it, at least not in 2012.