From Tumblr’s post:
Tumblr is a place where brilliant, creative, funny, impossible people shape culture. Some of you have even turned your passions into jobs: book deals, music careers, paid gigs with the Creatrs program. Now, (soon!) that opportunity will be available to any eligible Tumblr—poet, musician, fan artist, and misfit weirdo memelord alike.
This sounds like an extension of Tumblr’s Creatrs Network, which paired Tumblr users with advertisers. People will be able to make money off the advertising, but Tumblr disclosed that users “won’t be able to make money until you register for the [partner] program—which is coming soon.”