Keynote talk at 4th International Workshop on Social Recommender Systems (SRS 2013)
In conjunction with 22nd International World Wide Web Conference (WWW 2013). More details: http://cslinux0.comp.hkbu.edu.hk/~fwang/srs2013/
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Large-scale Social Recommendation Systems: Challenges and Opportunity
3. Outline
? About LinkedIn!
? Social Recommender Systems at LinkedIn!
? Social Graph Analysis!
? Virality in Social Recommender Systems!
? Scaling Challenges
3
11. Outline
? About LinkedIn!
? Social Recommender Systems at LinkedIn!
? Social Graph Analysis!
? Virality in Social Recommender Systems!
? Scaling Challenges
11
14. Outline
? Social Recommender Systems at LinkedIn!
? LinkedIn Today: Recommend News!
? Jobs Recommendation!
? Related Searches Recommendation!
? Social Graph Analysis!
? Virality in Social Recommender Systems!
? Scaling Challenges
14
15. Linkedin Today: News Recommendation
? Objective: serve valuable professional news, leading to
higher engagement as measured by metrics such as CTR
15
16. News Recommendation: Explore/Exploit
16
item j from a set of candidates
User i
with
user features
(e.g., industry,
behavioral features,
Demographic
features,……)
(i, j) : response yijvisits
Algorithm selects
(click or not)
Which item should we select?
! The item with highest predicted CTR
! An item for which we need data to
predict its CTR
Exploit
Explore
Agarwal et. al 2012
19. News Recommendations: Revised Algorithm
? Explore/Exploit scheme!
? Explore: choose an item at random with a small probability (e.g., 5%)!
? Exploit: choose highest scoring CTR item (e.g., 95%)!
? Temporal smoothing: more weight to recent data!
? Impression discounting: discount items with repeat views!
? Segmented model: segment users in CTR estimation!
? Opportunity: Multi-arm bandit problem
19
20. Outline
20
? Social Recommender Systems at LinkedIn!
? LinkedIn Today: Recommend News!
? Jobs Recommendations!
? Related Searches Recommendation!
? Social Graph Analysis!
? Social Update Stream and Virality!
? Scaling Challenges
21. Jobs Recommendation
? Goal: recommend dream jobs to job
seekers!
? Challenges!
? Lag between view and application, offer,
acceptance!
? High level of expectations
21
22. Jobs Recommendation
22
17
Corpus StatsJob
User Base
Filtered
title
geo
company
industry
description
functional area
…
Candidate
General
expertise
specialties
education
headline
geo
experience
Current Position
title
summary
tenure length
industry
functional area
…
Similarity
(candidate expertise, job description)
0.56
Similarity
(candidate specialties, job description)
0.2
Transition probability
(candidate industry, job industry)
0.43
Title Similarity
0.8
Similarity (headline, title)
0.7
.
.
.
derived
Matching
Binary
Exact matches:
geo, industry,
…
Soft
transition
probabilities,
similarity,
…
Text
Transition probabilities
Connectivity
yrs of experience to reach title
education needed for this title
…
Ensemble
Scorings
Bhasin et. al 2012
23. Magic Is In Feature Engineering
? Open to relocation?!
? Region similarity based on pro?le or network!
? Region transition probability!
? Predict members’ propensity to migrate and
potential regions
23
24. What Should You Transition To And When
24
? Probability of holding a title wrt time: spikes 12 months aligned
Wang et. al, WWW’13
25. Job Seeking: Socially Contagious
25
[Zhang, 2012]
? Prob. of quitting increases as the #of recently left connected colleague
26. Outline
26
? Social Recommender Systems at LinkedIn!
? LinkedIn Today: Recommend News!
? Jobs Recommendation!
? Related Searches Recommendation!
? Social Graph Analysis!
? Social Update Stream and Virality!
? Scaling Challenges
27. Related Searches Recommendation
? Millions of Searches everyday!
? Help users to explore and re?ne their queries
27
Reda et. al, CIKM’12
31. Outline
? About LinkedIn!
? Social Recommender Systems at LinkedIn!
? Social Graph Analysis!
? Virality in Social Recommender Systems!
? Scaling Challenges
31
39. Outline
? About LinkedIn!
? Social Recommender Systems at LinkedIn!
? Social Graph Analysis!
? Virality in Social Recommender Systems!
? Scaling Challenges
39
44. Skill Recommendation
? Predict a skill even if not
present in the pro?le!
? Based on likelihood of
member having a skill!
? Features: company, industry,
skills, ...
44
Pro?le
Tokenize
SkillsTagger
Phrases
Skills
Skills Classi?er
Pro?le features
Recommended Skills
45. Suggested Skill Endorsements
? Binary Classi?cation!
? Features!
? Company overlap, School overlap,
Industrial and functional area similarity,
Title similarity, Site interactions, Co-
interactions, ...
Candidate
generation
Classi?er
Features
- Company
- Title
- Industry
...
Suggested
Endorsements
45
48. Outline
? About LinkedIn!
? Social Recommender Systems at LinkedIn!
? Social Graph Analysis!
? Virality in Social Recommender Systems!
? Scaling Challenges
48
49. Scaling Challenges: Related Searches Example
? Kafka: publish-subscribe messaging system!
? Hadoop: MapReduce data processing system !
? Azkaban: Hadoop work?ow management tool!
? Voldemort: Key-value store
Metaphor
Hadoop
Search
Backend
Kafka
Voldemort
Related
Searches
Backend
Front
End
HDFS
49
50. Outline
? About LinkedIn!
? Social Recommender Systems at LinkedIn!
? Social Graph Analysis!
? Virality in Social Recommender Systems!
? Scaling Challenges
50
52. Acknowledgement
? Thanks to Data Team at LinkedIn: http://data.linkedin.com!
? We are hiring!!
? Contact: mtiwari[at]linkedin.com!
? Follow: @mitultiwari on Twitter
52
You!
Applied Reseacher/
Research Engineer