I just stumbled over this page in the Stack Exchange dropdown (top left corner).


cs50 - For students of HarvardX CS50x: Introduction to Computer Science

When I click on it I get the following message:

Warning: this site is currently in private beta for at least a few more days.

To log in, you must have commited to the Area 51 site proposal and received the invitation email. Click the invitation link in the email to log in!

However, the page on Area 51 does not exist, so it's impossible to get any further information.

So, what is going on? Apparently this is a private site for Harvard students?

I don't have a problem with that in general, but I wonder

  • a) Why is it part of the Stack Exchange family if it is a private site?
  • b) Why does it show up for me under Stack Exchange sites at all if it won't even let me have read access to it?

It seems that there are several of those sites, for example edx-cs-169-1x.

Is this some sort of pilot project?

  • 1
    There was a question a short while back from a professor looking for a way for his students to learn about Stack Exchange, perhaps a deal was struck somewhere? Commented Apr 7, 2014 at 21:03
  • 22
    That's because Area 51 doesn't exist, according to the government. ;o) Commented Apr 7, 2014 at 21:03
  • 1
    Seems like the error is in the "Area 51 site proposal" link; it appears to be auto-generated to a non-existent site proposal.
    – user102937
    Commented Apr 7, 2014 at 21:05
  • @RobertHarvey I thought of that too, but searching yielded no results either.
    – magnattic
    Commented Apr 7, 2014 at 21:06
  • 5
    That's because there is no CS50 proposal; there is only the beta site, which is not yet public, and therefore not searchable via Google.
    – user102937
    Commented Apr 7, 2014 at 21:09
  • 2
    @JohnnyBones Actually, the government acknowledged its existence last year :) Commented Apr 7, 2014 at 21:15
  • https://cs50.stackexchange.com/ is now open for the public! Commented Jul 11, 2015 at 14:15

2 Answers 2


We're not really ready to announce this quite yet, but you might surmise from the title that this is a site "For Students of HarvardX CS50x: Introduction to Computer Science."

The Area 51 link is just following a template that, in this case, doesn't apply.

  • 3
    Seems like you're leaking some implementation details...
    – user102937
    Commented Apr 7, 2014 at 21:12
  • 9
    Does this mean that the private Stack Exchange Enterprise option is no longer internal only and is also available for academic use? Maybe a competitor for Piazza? Commented Apr 7, 2014 at 21:17
  • 4
    Uh, exciting! I hope I did not spoil any surprise. You might want to hide it from the top bar until it is ready, though. I usually go through there to find interesting new SE sites, and am probably not the only one.
    – magnattic
    Commented Apr 7, 2014 at 21:28
  • 1
    @AustinHenley It honestly doesn't mean anything at this point.
    – Adam Lear StaffMod
    Commented Apr 7, 2014 at 21:28
  • 2
    Uh, the beta sites are still vulnerable to the breakin. I managed to create an account on this one (well, the other one) -- if sensitive data is going to be passed around I suggest you find a way to prevent that. Commented Apr 17, 2014 at 13:07
  • 2
    @Manishearth: Also, the questions are leaking into the Filtered Questions page. Commented Apr 17, 2014 at 21:03
  • 10
    You guys are reading waayy too much into this. Seriously. We're working with a series of online courses offered by top universities to see if a curriculum-specific companion Q&A could (a) help these programs to be more innovative and successful, and (b) provide any useful public artifacts for future audiences. We're not making these sites widely available to the public yet because this is still highly experimental and, frankly, so far the content would be of zero interest to anyone but the participants. Commented Apr 24, 2014 at 20:31
  • @RobertCartaino I am very excited by the idea of curriculum-specific companion Q&A sites, it's great that you're looking into this
    – user241462
    Commented Apr 25, 2014 at 15:54
  • David and @Robert - any updates, almost year later? Is this still an experiment? Is it successful? Commented Mar 19, 2015 at 12:38
  • 2
    @ShadowWizard It's not an ideal fit for our engine, but the administrators have conveyed that they wish to continuing using the sites we have, but we will not likely be creating any more. Commented Mar 19, 2015 at 13:55
  • @Robert thanks the update. As it stands now, those two sites are considered "private beta" e.g. they don't appear in the sites list or in SEDE. Any plan to change this? Commented Mar 19, 2015 at 13:56
  • 2
    @ShadowWizard There was something about the "private beta" settings that allow them to work better with our network, so we kept it that way. It might have been the reduced reputation levels or that they would not be an entirely visible part of our network listings, but I cannot recall the specifics. Commented Mar 19, 2015 at 13:59
  • @Robert yes this makes sense, but what if users here want to run stats on those two sites? Usually that's what we have SEDE for, but they don't appear in there. Is it possible to manually add them or something like that? Commented Mar 19, 2015 at 14:02
  • 1
    @ShadowWizard No, we're not going to be putting any further development resources into the edX sites. They're just not really part of the Stack Exchange network of sites. Commented Mar 19, 2015 at 14:05
  • @Robert cheers, thanks again! One final request, if you can please take a look and post official response on this, it would be great. :) Commented Mar 19, 2015 at 14:07

The new beta Stack Exchange site for students of UC BerkeleyX's CS169.1x Engineering Software as a Service course on edX is now active. However, it is still not listed in the sites list on StackExchange.com, and the sidebar still appears to indicate that it's as a private beta, though it's actually publicly accessible.

Students are linked to this site by the "Discussion" tab when they're viewing the course materials, and from the course introduction.

We'll post updates to this "Course Info" page as we go along, however, our primary communication channel will be our interactive forum, where we’ll all contribute to an ongoing discussion of the material.

The site supports edX as a new login provider:

Registration on the site also requires agreement to a modification to the typical privacy policy: information entered on the site may also be shared with edX. (Trivia: When this policy was added during the beta, this meant that the handful of existing accounts had to be deleted for legal reasons.)

  • 24
    "interactive forum" Oh bother. Commented Apr 19, 2014 at 13:36
  • 2
    I expect them to benefit from Stack Exchange regardless of what they call it.
    – Jeremy
    Commented Apr 19, 2014 at 15:11
  • 7
    Well they certainly seem to be treating it as a forum. Some of the questions are terribile.
    – user226333
    Commented May 8, 2014 at 3:55

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