Harnessing Collective Intelligence – Stack Exchange

Harnessing Collective Intelligence - Stack Exchange

Stack Exchange is a network of question and answer websites on a range of topics. Currently there are 46 websites in the network ranging from programming to mechanical to gaming to cooking.


Harnessing Collective Intelligence - Stack Exchange
Hot questions on the Stack Exchange network

The concept behind Stack Exchange is that each website in the network is a combination or synthesis of a blog, a wiki, a forum and sites like Digg and Reddit that users can easily participate in by utilising OpenID for user accounts.

Users are able to ask questions as they would on a forum, tagged like a blog post, that can be responded to by numerous other users. Each question and response can be elaborated on by other users as in a wiki to either gain a greater understanding of the issue, or to provide a better explanation or solution to the question. Tags are also managed as individual wikis, allowing discussions on each tag through a managed wiki environment.

Responses are managed more like blog comments than like a forum. Each question is show like a blog post and responses appear as comments that can also be commented on. Each response can then be voted on by the community so as to determine the best answer. Users that respond, providing helpful solutions are rewarded with reputation and subsequent reputation based privileges. Answers that are chosen as the best response provide even more reputation to the responder.

Some privileges that can be earned include:

  • Flagging posts
  • Reducing ads
  • Voting up an answer
  • Voting down an answer
  • Creating tags
  • Access moderator tools
  • More!

Comparison to other Web 2.0 Applications

Harnessing Collective Intelligence - Stack Exchange
A question about finite verbs on the English Language Stack Exchange website.

Stack Exchange provides similar functionality to applications like the various forum, wiki and blog tools combined with Digg and Reddit, and as such addresses the various inadequacies of all of these different platforms.

Bloggers often utilise their blog to ask questions and hope for answers from readers. Similarly bloggers that are reading other blogs may answer questions, but there is often little incentive to do this.

Forums provide a community, usually on a specific topic, where users can interact and discuss the forum topic. Participating in a forum can often be difficult as most forums require users to register an account specifically for that forum. This is fine for users that spend a lot of time on a forum, but for users that only want an answer to one question, this can be time consuming and limits potential responses to members of the particular forum. Stack Exchange addresses this problem by utilising OpenID to allow anyone with an OpenID account, including Google Accounts and Facebook accounts, to login and post their question, or provide their response without the need to create a new account. A user can easily migrate between Stack Exchange network websites using their OpenID.

Harnessing Collective Intelligence - Stack Exchange
A question about NAT within companies on the Server Fault Stack Exchange website.

Wiki’s allow for community management of a topic and discussion surrounding that topic, but is not ideal for inexperienced users and can have a steep learning curve. They also do not allow for a simple question and answer scenario, but rely on users creating and editing content that may or may not answer a question.

Digg and Reddit allow for user voting on and categorising content that they like, but this requires content to be submitted from external sites.


This application provides a simple way for users to get quick answers by providing reputation based incentives that give users more power on the website network in a way that makes it convenient for users to participate. This encourages interaction between the collective intelligence of users on the internet to come to provide answers to questions that are indexed in search engines, allowing other users to find answers, and potentially participate as well, answering a question that they know the answer to.

Potential legal and ethical issues

The main legal and ethical issues that I can see come down to who owns the intellectual property in the user responses. Is it the users? Is it the website owners? The Stack Exchange website, and all of the websites on their network make the content license and usage clear in the footer of every page.

User contributions are all licensed under the Creative Commons 2.5 Wiki license (Creative Commons 2.5 attribution and share-alike). According to the Stack Overflow blog article titled “Attribution Required” (Stack Overflow was the first website in the network, focused on programming) by Jeff Atwood (2009) all content is provided in a data dump as well as through the website so as to easily allow anyone to reuse and remix the data. However, all uses of the content on another website must be attributed with a clear indication of where it was from, a hyperlink to the original question, the name of every author who’s contribution has been reused, and a hyperlink to each author’s profile page.

The use of a creative commons license encourages fair sharing of the content elsewhere, but means that the authors rights are protected and they will continue to receive credit for their intellectual property and retains rights to it should their intellectual property not be used according to the license terms.


Stack Exchange. (n.d.). What is Stack Exchange? Retrieved March 14, 2011. http://stackexchange.com/about

Atwood, J. (2009). Attribution required. Retrieved March 14, 2011. http://blog.stackoverflow.com/2009/06/attribution-required/

Note: This blog post is part of a series of blog posts that form assessment item #2 for INB347 – Web 2.0 Applications.

2 thoughts on “Harnessing Collective Intelligence – Stack Exchange”

  1. I really enjoyed your blog post. I think the Stack Exchange is an exellent example of harnessing the collective intelligence of the community members. I also found it very interesting about your discussion around the legal issues. It is definitely something that future organistations operating in this space will need to be aware of.

  2. Hi Brendan, it’s a fantastic tool to use, I’ve used the original Stack Overflow many times, both to ask questions and provide answers, and it really is fantastic because it doesn’t take long to answer and help someone out, and it usually doesn’t take long to get an answer when you ask a question either. Their Creative Commons license makes sense to me, because it doesn’t take ownership away from the original author but it allows reuse. It’s definitely an issue that needs to be treated carefully in any organisation.

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