iCloud Backup and Flickr
My iPhone's backup has been holding steady at around ~4.2GB and I had never seen an alert about not having enough space until last Friday. I finally figured out that the latest Flickr app update adds 1.5GB to the iCloud backup and turning that off will get the backup back to its usual size.
What in the world is Flickr putting in the iCloud Backup? I'm guessing mostly images that are already backed up in their 1TB of free space. :/