Remember all the conferences where Flickr was praised as a platform to bring museum and archive collections to the people? Well, for quite some time now they do not provide support for new GLAMs to join the program.
I am sure that like Kenny, there will be a next chapter in the evolving drama. Unlike Flickr Wikimedia Commons is very much still in business to welcome new cooperation with GLAMs that will bring its cultural heritage to a global audience. The number of conferences where you may have heard about the possibilities are rising and there are plenty of people, myself included, who will be happy to help you in the direction of Commons.