Flickr. It is quite understandable that those who do are happy, it is a great service to them. It is however no longer an example that can be followed.
There used to be a program where technicians from Flickr helped a GLAM set up a presence. In order to reduce costs, this popular service was discontinued. At Commons, we are quite happy to welcome collaboration with Galleries, Libraries, Archives and Museums. The service provided is one provided by volunteers. It is improving because of the lessons learned.
The challenge will be to do better then Flickr and be able to welcome new partners even when the current trickle changes into a flood.