Their most popular property ended up being Flickr, and they let it rot when smartphones and apps started being popular 10 years ago. Instead pro users fled to 500px and other communities, and social users wen to Instagram.
Flickr came from Game Neverending. It was an in-game feature and it did so well, the game was never released. That came from Caterina Fake and Stewart Butterfield's team and their innovative work at Ludicorp. It was purchased and then became a squandered opportunity by Yahoo!
And they absolutely let it stagnate. The apps that were available for phones (once there were apps) were often pretty terrible, from my recollection.