Yahoo! AnswersCommunity Moderation

Micah Alpern, Director of User ExperienceYahoo! Search

•Yahoo! AnswersAsk, Answer, Discover

• 1.2 million Q&A per day

• Experiential Knowledge

•Yahoo! AnswersAsk, Answer, Discover

• 1.2 million Q&A per day

• Experiential Knowledge

Activity

Activity

Answers is a marketplace

•People want lots of good answers to their questions quickly.

This means wide distribution of your freshest content.

Higher visibility for abuse in Questions than Answers.

“If you don't fix it right away, it's not worth fixing.”

by getxsickphotography

Traditional Moderation Failed

•As Answers grew traditional moderation methods failed to scale with the community.

•Manual customer care systems: Had slow response times

Treated all abuse reports the same

Had high false positive and false negative rates

Were high cost and scaled up with traffic

Machine learning?

A team of PHDs worked on a black box abuse classifier.

Pre-filter of bad content to be reviewed by Customer Care.

Could only handle questions, not the answers

After a while that broke as well

60% of reports were fake abuse by users trying to report others.

Community Moderation

• Deployed a newCommunity Moderation system  Empowered trusted Answers users to help moderate content by allowing their report abuse actions to automatically delete content.

 System didn’t reveal reputation scores to users,

Encouraged them to report accurately so they could gain more community influence.

Illustration by Bryce Glass

To address these challenges:

Reputation System

Answers Moderation Model

Hide Content

Item?

ContentReporter

Author

Answers Moderation ModelREPORTER

Abuse Suspicion Reputation

REPORTER Community InvestmentReputation

User’s Abusive

Reputation

Confirmed Abuse

Reporter Reputation

Abuse Reporter

Bootstrap Reputation

AbuseReporter

Reputation

CONTENT ITEM AbuseReputation

AUTHOROverall Asker

Reputation

AUTHOROverall Answerer

Reputation

AUTHOROverall Asker

Reputation

Question Quality

Reputation

AUTHOROverall

Answerer Reputation

Answer Quality

Reputation

Hide Content

Item?

the story of a report

an abuse report comes in

We need to decided: Who do we believe? Do we hide the content?

A question is asked..

Author Reporter

The content

A question is asked..

What do we know about the content? Have others reported it

Machined learned “Junk detector” score

Language specific

Requires tons of training data

!= a quality detector

CONTENT ITEM

AbuseReputation

the reporter

What do we know about the reporter?

Reporter

08.17.08 4:41pm

08.20.08 6:23 pm

10.04.08 1:08 pm

11.06.08 7:03 am

Past reporting behavior

hiddennot

hiddenhide overturned

Outcome

not hidden

Confirmed Abuse

Reporter Reputation CONTENT

ITEM AbuseReputation

AbuseReporter

Reputation Past reporting performance

and it’s outcome

For many reporters we don’t have enough feedback.

How do we solve the cold start problem?

Cold Start:Reporter Reputation

Reporter

Suspicion: Implied Karma

Hard evidence

Examine signals across synonymous identities

Confirmed Abuse

Reporter Reputation Abuse

Reporter Reputation

CONTENT ITEM AbuseReputation

Take this result and update the running reputation of the content reported.

Reporter’s Abuse

Suspicion Reputation

Reporter’s Community InvestmentReputation

User’s Abusive

Reputation

Abuse Reporter

Bootstrap Reputation

Compared to

Illustration by Bryce Glass

Do we trust the author?How good are they at Asking questions?How good are they at Answering?Do they have a history of abuse?

AUTHOROverall Asker

Reputation

AUTHOROverall Answerer

Reputation

AUTHOROverall Asker

Reputation

Question Quality

Reputation

AUTHOROverall

Answerer Reputation

Answer Quality

Reputation

Users Abusive

Reputation

we make a decision

an abuse report comes in

A question is asked..

Author Reporter

decisions can be revised

an abuse report comes in

A question is asked..

Author Reporter

Trust level is re-instated andtemporary protection assigned.

Trust level for Reporting is decreased.

CraigsListAfter 3 flags the post is deletedOther systems: Ignore new user flags

In Answers:• Its harder to remove content from good contributors.

• Easier for a even a new person to remove a spammer.

Naive moderation

So how did we do?

Speed

Accuracy

Concussion

• Reputation system helped Answers:

Scale & empower the community to mange abuse

Provide a better experience to Askers and Answerers

Questions?

Bryce Glass

Randy Farmer

Ori Zaltzman

http://buildingreputation.com/

Micah Alpern

malpern@alpern.org

twitter:malpern

SPAM

•  “We have other methods for identifying and dealing with spam, but as a very popular site we are a target for spammers so are continually upping our game to find new ways to identify them quicker and remove their content faster (though we shouldn’t share the methods we take). We recognize spam damages the experience for our users and so are committed to reducing spam on Answers as much as possible.”

Chat and Low quality content

• “You mention this a bit in the presentation, but generally we acknowledge there are different types of questions being asked and answered on the site and accept that currently we’re limited in how we are identifying and highlighting knowledge based Q&A vs Social Q&A. However, we are looking at ways to easier promote the type of content a user wants to see.”

Accuracy

• “focus is on experiential knowledge, practical help based on someone’s opinion or experience. Different type of knowledge than covered by wikipedia. We don’t want to publish content which is misleading, incorrect or harmful but use the “report abuse” system and our trusted users to balance any dubious advice.