Reference & Learning
Encyclopaedias, Q&A sites and reference works that stopped being updated.
5 projects
Yahoo Answers
The internet's strangest Q&A community
2005–2021
Reference & Learning
About.com
Seven hundred human guides, four owners, one quiet rebrand
1997–2017
Reference & Learning
Knol
Google's signed, ad-sharing answer to Wikipedia, opened in 2008 and closed in 2012
2008–2012
Reference & Learning
Encarta
The encyclopedia on a CD, killed by a website
1993–2009
Reference & Learning
Google Answers
Pay a researcher $2 to $200 for an answer: Google's first paid product, closed in 2006 as Yahoo Answers took off
2002–2006
Reference & Learning