They've been noted before for being similar to StackExchange.
You can lookup "whois" info for a site to see who owns it.. this is definitely a separate site.
StackExchange, SO, SF, and related sites:
Registrant Name: Sysadmin Team
Registrant Organization: Stack Exchange, Inc.
Registrant Street: 1 Exchange Plaza , Floor 26
Registrant City: New York
Registrant State/Province: NY
Registrant Postal Code: 10006
Technical contacts are "firstname.lastname@example.org".
Info for Udacity:
Registrant Name: Domain Administrator
Registrant Organization: Udacity, Inc.
Registrant Street: 2465 Latham Street, 3rd Floor,
Registrant City: Mountain View
Registrant State/Province: CA
Registrant Postal Code: 94040
Technical contacts are "email@example.com"