Remember Tumblr? It seems they are working on a tipping feature. I found references to ‘Enable Tip Jar to start accepting tips’ and ‘Your personal and deposit details have been verified’ in their iOS app. There is also what appears to be a low resolution version of the cash with wings emoji 💸.
Tumblr also appears to be working with Stripe on their tipping feature as another reference reads “To enable your Tip Jar we’re going to direct you to our payment partner, Stripe so you can safely provide your personal and deposit details to get paid. Don’t worry, we’ll bring you back here when your done.”
It isn’t clear if 100% of the tip goes to the creator but it probably safe to assume that it does because otherwise Apple wouldn’t allow the app in their App Store.