The owner of the profile of the person who answered your question (whoever he is) seems to have changed his username from "Craig S Wright" to Frank Blu on Dec 12th 2015. He also seems to have deleted, on that same day, every post he made on Quora after Dec 11 2014.
The titles of the questions on which he posted revolved a lot around cryptocurrencies, cryptography and supercomputers, as well as finance and economics. Some example of questions to which he contributed are:
"How large will the Bitcoin blockchain be in November 2015?" "How would I estimate the cost of setting up a 100 Tera-Flop server at my..." "Why is gold considered so precious and why does it have such high prices..." "Are there better uses of stimulus funds than others?"
His earliest activity on the site is the creation of a topic called CSCSS, on Jul 30th 2012.
I'm not sure I believe his comments fully in his latest video though. It seems he's been conflicted for a long time on whether to reveal himself but for all the times he says he wants to be left alone, he easily could have but yet here he is.
https://www.quora.com/Who-is-most-likely-Satoshi-Nakamoto/an...