Comparison of Q&A sites


The following is a list of websites that follow a question-and-answer format. The list contains only websites for which an article exists, dedicated either wholly or at least partly to the websites.
For the humor "Q&A site" format first popularized by Forum 2000 and The Conversatron, see Q&A comedy website.
WebsiteFoundedClosedDescription/focusLanguages availableCopyrighting of user contributionsRegistration required?Price
Answers.comAll topicsEnglishFree
Ask.fmSocial topics49 languagesYes
AskbotN/Avariesvariesvaries
Ask MetaFilterMany topicsEnglishAll posts are copyright to their original authors.No to browse, yes to contribute
AvvoLegalEnglishYes
Baidu KnowsMany topicsChineseNo to browse, yes to contribute
BlikBookN/ALocal academicEnglishYes
BlurtitAll topicsEnglishYes
BrainlyAcademic12 languagesContributed content owned by its authorNo to browse, yes to contribute
Brilliant.orgScience, technology, mathEnglishUser retains ownership; Brilliant can use, distribute, modify.Yes/Paid$599.99 for life time use
ChaChaMany topicsEnglishOwned by ChaChaN/A
CheggAcademicEnglishOwned by Chegg Inc.Yes / paid
eNotesAcademicEnglishOwned by eNotes.comYes / paid$14.99/month; $49.99/year
Experts-ExchangeInformation technologyYes / paid
FixyaConsumer productsEnglishYes
Google AnswersEnglishYes
Google Questions and AnswersMany topicsRussian, Chinese, English, FrenchN/A
Gutefrage.netGermanYesFree
HealthTapHealth informationEnglishNo
Internet OracleAll topics EnglishNo
JellyAll topicsEnglish
Knowledge INMany topicsKorean
LinkedIn AnswersBusinessYes
MadSci NetworkScienceEnglish
Mahalo.comMany topicsEnglishN/A
Ответы@Mail.RuRussian
ProfNetJournalistsEnglishYes
QuoraMany topics22 languagesContributions owned by the author. Quora granted "worldwide, non-exclusive, royalty-free license" to content use, distribution, or modification.Yes, except to view single answersFree
RedditAll topicsDepends on subredditNo to browse, yes to contribute
SharecareHealth and wellnessEnglishNo
Spring.me All topicsEnglishYes
Stack ExchangeMany topicsEnglish Contributions owned by the author. Contributions "perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution Share Alike license".No to browse and answer, yes to ask and contribute fully. Some topics allow asking as a guest.
Stips2006All topicsHebrewYes
The Straight Dope 2018Many topicsEnglishNo
TranstutorsAcademicEnglishOwned and operated by Transweb Educational ServicesYes / paid
TXN ?SportsEnglishNo
UclueMany topicsEnglishYes
WikiAnswers2018Many topicsSubsumed by Answers.com
English Wikipedia Reference DeskMany topicsEnglishCC-BY-SA 3.0 and GFDL dual licenseNo
Yahoo! AnswersAll topics13 languagesContributions owned by the author. Yahoo retains rights to the use, distribution or modification.No
ZhihuMany topicsChinese and a few othersOwned and operated by the original authors.Yes, except to view answers of questions when directed from search engine-