I was looking at forums.udacity.com, and noticed that the badge system and user system are much like all Stack Exchange sites.

However, there is no mention of that site being part of Stack Exchange anywhere, and the home page looks much different than Stack Exchange's.

Is this site really part of Stack Exchange? Or do they just look similar?


1 Answer 1


Nope. It's a clone, or a site that looks similar, but is not part of the Stack Exchange network. All SE sites are under the stackexchange.com domain name.

The following sites have their own domain name because they are older:

There is also AskUbuntu.com, a special exception that was formed because of a partnership between Ubuntu and Stack Exchange. However, this sort of relationship does not happen anymore (there was a dedicated facebook dev site, but that was phased out). You have to go through Area 51 to get a site approved.

And, there is MathOverflow.net, which was started as an SE 1.0 site in September 2009. It eventually joined the network in June 2013, yet it is still owned by the independent entity MathOverflow and its presence in the network is governed by an individual agreement.

Plus, they have double diamond users. What does that even mean???

  • 3
    SE 1.0 sites had double-diamond users too; they were admins. Most recently seen on pre-migration MathOverflow. Apr 17, 2014 at 3:43
  • Good answer! Thanks!
    – A.J. Uppal
    Apr 17, 2014 at 3:54
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    There are more SE sites not under stackexchange.com, e.g., mathoverflow.net.
    – 4ae1e1
    Apr 17, 2014 at 4:12
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    @KevinSayHi: Actually, MathOverflow was (not-so-)recently inaugurated into the SE network. Apr 17, 2014 at 4:16
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    @BoltClock'saUnicorn That is true, but I think that Kevin was referring to the fact that mathoverflow.net is not a subdomain of stackexchange.com.
    – apnorton
    Apr 17, 2014 at 5:01
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    @BoltClock'saUnicorn Oh I should have said "... not under the domain name stackexchange.com" to clear any ambiguity (it should have been clear from context, though).
    – 4ae1e1
    Apr 17, 2014 at 5:12
  • @KevinSayHi There was no ambiguity. MathOverflow's status as part of StackExchange but not but not under stackexchange.com was quite clear. There are serverfault and superuser as well. Apr 17, 2014 at 9:21
  • @FeralOink Of course there's no ambiguity in the fact. I mean, BoltClock's a Unicorn might have interpreted my comment as MathOverflow is not under the supervision of StackExchange.
    – 4ae1e1
    Apr 17, 2014 at 16:05
  • You said, "All SE sites are under the stackexchange.com domain name (besides SO, SF, SU, and AU)". What is AU? Apr 24, 2014 at 15:12
  • @FeralOink, Ask Ubuntu, the site for the Ubuntu distribution of Linux.
    – gunr2171
    Apr 24, 2014 at 16:11
  • The information given here regarding MO is possibly ambigous. mathoverflow.net is at the moment part of the Stack Exchange network. Thus while in some sense it is true that MathOverflow is part of Stack Exchange (the site is part of the network), in another sense it is however not true, as MathOverflow is an independent nonprofit nonstock corporation in the state of Delaware and not part of Stack Exchange, Inc. I would not mention it in parallel with S[OFU]; it is also more a special case site like AU.
    – quid
    Apr 24, 2014 at 18:40
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    @quid, agreed. I honestly don't know anything about MathOverflow, visited it for the first time today. I just took the information from BoltClock. If you want to edit the question, go for it.
    – gunr2171
    Apr 24, 2014 at 18:42

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