App.net was a social network started by Dalton Caldwell and Bryan Berg in 2012. It championed paid-for social networks, starting at $50/yr before dropping to $36/yr and eventually introducing a "free tier". It closed in March 2017.
In 2015, App.net became a "ghost ship", with only previous employees working on a contract basis as needed.
Many Pnut users met on App.net. Pnut was inspired and built by and built to replace App.net, once it was clear it would fold.
The domain has since been sold.