Simple enough question. I notice Stack Overflow has over 100,000 users — huge congrats guys! Can you share exactly how old Stack Overflow is? Also, what percentage of the 100,000 are active? Can you provide any statistical breakdown on the activity?

Thoroughly impressed and looking forward to Stack Overflow's bright future.

UPDATE: I have found some fascinating statistics via Twitter for Stack Overflow. They do not provide a complete answer to my question, but some interesting details may be derived. For example, how many visits / person etc.


  • Ok, so I think going from the private beta or July 31, 2008 makes the most sense, since that's when the site actually started accumulating users. So Olafur Waage, jjnguy, wallaceno9, and Henk Holterman all reach that same conclusion in a different way. So... what about my second question? What percentage of the 100,000 users are active? Just curious! – Joshua Nov 24 '09 at 4:46

Well, the private beta started July 31st 2008.

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Question #1 was asked July 31st, 2008 21:26:37Z.

Unfortunately its timeless wisdom was deleted and is now only visible to those with 10k rep or more.

Question #2 (Post ID is 4), visible to all, was asked shortly after at 21:42:52Z

The public beta opened September 15th, 2008. This is the point that Stackoverflow was officially open to one and all.

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  • 6
    I'll let you savor the moment you become a 10k user by not giving away the contents of the question. – Pollyanna Nov 17 '09 at 23:19
  • It looks like I joined on September 17th, 2008. I didn't realize that I joined just 2 days after the site went public. – Gabe Apr 8 '11 at 6:14

From April 16, 2008:

Introducing Stackoverflow.com

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As old as the community is.

Also you could look at when Jeff Atwood became a member.

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  • No real time when Jeff Atwood became a member (just says 1 year) -- or I missed it on the page somehow. Also the 'community' link shows the age that a moderation background process was created -- apparently after real users :) – Joshua Nov 24 '09 at 4:45
  • Josh: hover on the "member for" number and there will be a tooltip saying 2008-07-31 – perbert Nov 24 '09 at 7:26

In the Stack Exchange - All Sites page, in the list view with Sort by: Oldest you can find all the site's age in descending order.

Or simply use this URL for the same option: http://stackexchange.com/sites?view=list#oldest

Any SE site's age

Note: It won't say when was the sites were started. But giving the site's current age.

Another option to check the each site's starting date:

In any site, when you are navigate to the Users -> reputation tab -> hover the all tab it will display the text as starting date of the site to today.

For Stack Overflow the starting date is 2008-07-31

The URL path is: https://stackoverflow.com/users?tab=Reputation&filter=all

Stack Overflow starting date

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