Flickr are giving a nice gift to all of its current users, 3 months of pro service for free! In an effort to become the number one photography site it's been going under many improvements, including some design changes and updates to its mobile apps.
The site needed changes with its design because the whole site in general was being neglected. The user experience and design were becoming very old and boring, giving sites like 500px the advantage with their minimalistic full width design.
You can get your 3 months of pro service here.