I was wondering whether one could take inspiration in how stackoverflow/stackexchange works, when implementing an online portal, or whether that could be a patent infringement.

Some examples of features I know from SO/SE but not elsewhere:

  • Initial barrier for new users, such as to writing comments, or editing other posts
  • Some highly active questions/answers have increased barriers
  • Many pointers to checking existing questions, to prevent duplicates
  • Flagging of duplicates
  • References shown on the right to questions mentioned anywhere on the question page
  • Community wikis
  • Answer your own question
  • The combination of features they have - some (many?) aren't unique to SE, for example voting on questions/answers, a reputation/points system, commenting on answers, a moderator system, accepting answers, ... but maybe the particular combination features that SO/SE has is patented in some way?

I'm not primarily asking about specific algorithms, such as the one that determines the order of answers, or their search engine internals. I'm asking about anything that a user of the website could know about and copy.

I'm sure many more aspects are what made stackoverflow et al popular, and running such a site doesn't seem simple. My question is about whether it would be legally possible to copy it. Since this site is about US law, I'm happy about answers about US law, but would also be interested in the situation in other countries.

  • I don't know if SO has any patents, but copyright is much more likely to be an issue for you.
    – Eric S
    Jul 18 at 20:07
  • @GeorgeWhite I was concerned about copying screens and graphics.
    – Eric S
    Jul 19 at 15:47
  • Thanks, @EricS - does copyright only apply to graphical design choices, or also some of the functional features of SO? Either way, thank you for your answer.
    – dasWesen
    Jul 19 at 16:30
  • 2
    Copyright might cover the actual graphics of the website along with the underlying code. You should never copy any user facing code unless it is licensed as it might be if you are using a framework such as WordPress.
    – Eric S
    Jul 19 at 16:37
  • Thank you very much!
    – dasWesen
    Jul 20 at 8:00

2 Answers 2


I went to Lens and searched for patents assigned to "stack". I could find no assignees with the word "stack" as part of their name. This doesn't mean that Stack Exchange doesn't have patents as they could have some other entity for assigning ownership of patents. Also, there is also the possibility that there are some patents owned by others that Stack Exchanged licensed which might be relevant to a site built by you. Another search using the terms "question and answer" and "website" yielded 7819 active patents. Many are irrelevant, I'm sure, but it would bare some investigation.

As for other forms of intellectual property, copyright and design patents both may be relevant. I would avoid simply copying the look and feel exactly. You should never copy any user facing code unless it is licensed as it might be if you are using a framework such as WordPress.


Patents are granted for inventions that are new, useful, and non-obvious. To be patentable, an invention must also be something that is not simply an improvement on an existing invention.

The features you mentioned, such as the initial barrier for new users, flagging of duplicates, and references to other questions, are all relatively common features of Q&A websites. These features would likely be considered novel or non-obvious enough to be patented.

The combination of features that Stack Overflow uses may be unique, but that does not necessarily mean that it is patentable. To be patentable, the combination of features must also be non-obvious. This means that it must be something other than something obvious to a person skilled in the art.

  • It is 100% wrong that patents are not given for improvements. The first section of the patent law in US is “ Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, ”
    – George White
    Aug 18 at 19:25
  • 1
    I think this is a worthy answer should you make an edit based on George White's comment. Perhaps changing "not simply an improvement..." to "not simply an obvious improvement...". Should you make that edit I would be happy to offset the down vote. Also, welcome to Ask Patents and thank you for answer.
    – Eric S
    Aug 20 at 0:44
  • 1
    OP - if you edit your answer, look at the last sentence of paragraph 2. I think you meant to include the word “not” . That and EricS comment would make it a reasonable answer. Many people do have a misunderstanding about improvements. Also, they do not need to be monumental but they do need to be novel and non-obvious as you state. And welcome to Ask Patents.
    – George White
    Aug 20 at 15:36

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