Twitter took Gene X Hwang's username and only offered him "some merch."
Hwang confirmed to Ars today that "there was no financial compensation" offered to him. The company offered "to switch the @x account and its history/followers etc to a new handle once I select one that is available," Hwang told us. "They also offered some merch and to meet with the management team as well."
I remember reading ages ago about how highly sought after and how much single-character twitter handles would potentially sell for, since there's only 26 in the entire world. Now all this person got was a t-shirt.