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Hashtag: #hunchgraphs
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Malcolm Gladwell Title:
What Chipotle, Glenn Beck and
Alien Abductions Teach Us About
the Future of the Web
8/7/2019 graphs (by @cdixon and @hunch)
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Graphs 101
A BNodeNode
Edge
Social networks (Facebook): nodes are people, edges “friendship”
Communication graph (Skype): nodes are people, edges communications
Taste graph (Hunch): nodes are people, edges taste similarity
Search ranking graph (Google): nodes are pages, edges links
Interest graph (Twitter, Instagram): nodes are people, edges interest
8/7/2019 graphs (by @cdixon and @hunch)
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First Graph Theory:Euler’s 7 bridges of Koeningsberg
•Convert land to nodes & bridges to edges•Any node that is passed through must haveeven number of edges•Thus only solvable if you have 0 or 2 nodeswith odd number of edges
•Is it possible to traverse the town & crosseach bridge exactly once?
8/7/2019 graphs (by @cdixon and @hunch)
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Undirected Graph: Relationship Symmetric(Friendship)
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Directed Graph: Relationship Non-symmetric(Like, follow, subscribe)
One could argue that Twitter’s main innovation was making edges non-
symmetric (directed), turned social network into publishing platform
Facebook began as undirected friend graph but has since bolted directed“like” graph on top of it.
8/7/2019 graphs (by @cdixon and @hunch)
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Interlude: data fun
8/7/2019 graphs (by @cdixon and @hunch)
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Averages
Twitter :
Number of followers: 62.97 per user Number of followees: 43.52 per user
Facebook:Number of facebook likes: 217.2 per item (liked)Number of facebook likes: 29.30 per user
But distributions are interestingly different...
8/7/2019 graphs (by @cdixon and @hunch)
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Twitter distributions are power curves
Spike of “# following” curve around 20 due to old onboarding process (?)
Distribution of # of followers you have Distribution of # of people you follow
8/7/2019 graphs (by @cdixon and @hunch)
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Facebook friends is more like a bell curve
y = number of people; x = number of friends for those people
8/7/2019 graphs (by @cdixon and @hunch)
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Facebook “likes” similar to Twitter (sincealso non-symmetric?)
8/7/2019 graphs (by @cdixon and @hunch)
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Some real world applications
8/7/2019 graphs (by @cdixon and @hunch)
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Marketing
Telecom company tested using phone call graph to use for direct mail*
Targeting network neighbors of purchasers dominated other targeting techniques.
Today, Facebook and many ad networks use similar targeting for online ads.
* “Network-Based Marketing: IdentifyingLikely Adopters via Consumer Networks - Shawndra Hill, Foster
Provost and Chris Volinsky
AB
purchased product
C
similar demographics to A
communicates with A
B more likely to buy than C
8/7/2019 graphs (by @cdixon and @hunch)
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Defense
You can infer organizational hierarchies from communication patterns.
Governments use this to map rogue organizations.
Boss Henchman
A Bcalls
responds immediately
ABcalls
responds slowly
A B
THEREFORE
8/7/2019 graphs (by @cdixon and @hunch)
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Google founders’ $200B idea
Words and documents are nodes, connected by occurrence
PageRank: Links are directed graph
Node Node
8/7/2019 graphs (by @cdixon and @hunch)
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Gratuitous XKCD comic
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Building graphs
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Start with smaller graph:Bowling Pin Strategy
H a r v a r d
B o s t o n
a r e a c o l l e g e s
B o s t o n
a r e a c o l l e g e s
M o r e c o l l e g e s
M o r e c o l l e g e s
E v e r y o n e
E
v e r y o n e
• Utility is proportional to square of network coverage, but how to start?• Shrink size of the initial network and grow from there• Also try to choose a sub-network with natural ‘spillover’ effects
•In this example, students at one college tend to have friends at others
8/7/2019 graphs (by @cdixon and @hunch)
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Find clusters within existing graphs
A lot of people in the 90s thought dating would be “winner take all” - but didn’t account for clustered graph structure
8/7/2019 graphs (by @cdixon and @hunch)
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Introducing Overlap of Buyers/Sellers can addDifferentiation even in Entrenched Graphs
Heterogeneousbuyers/sellers Hybrid
Homogenousbuyers/sellers
For heterogenous buyers/sellers consider “Ladies night strategy”
8/7/2019 graphs (by @cdixon and @hunch)
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Graph wars
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Facebook vs Google on opening social graphs
Google:
8/7/2019 graphs (by @cdixon and @hunch)
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When to Interoperate?
Metcalfe’s Law
Network value ~ (nodes)2
Corollary:
Little guy benefits more than big guy
Little guy joins network and:•Big guy gains small incremental increase in connections•Little guy gains value of the many existing connections
•That’s why AIM (as incumbent big player) resisted whenYahoo! & Google wanted to interoperate for IM
Little guy
Big guy
8/7/2019 graphs (by @cdixon and @hunch)
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On the other hand…
• Each little guy benefits more than the big guy from interoperating
• But thousands of little guys relying on the big guy solidifies big guy position
• Facebook realized this and introduced Facebook Apps, Connect and other “interoperating” features to prevent the “social network decay” that destroyed
previous social networks.
Facebook dev platform
8/7/2019 graphs (by @cdixon and @hunch)
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Shameless self-promotion: taste graphs
8/7/2019 graphs (by @cdixon and @hunch)
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Tastemates as Basis of a Graph
CarcasonneModern Conflict
?
Enigmo
Someone out there must enjoy the same tile/strategy games I do…And chances are they are not (yet, anyway) my friend
8/7/2019 graphs (by @cdixon and @hunch)
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The “Cold Start” Challengefor Taste-Based Predictions
How to provide initial recommendations for a new user?
Force train, then predict
Assume tastes are driven by social graph
Leverage cross-vertical knowledge andadjacent known nodes in Taste Graph
8/7/2019 graphs (by @cdixon and @hunch)
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One Cold Start Solution:Propagate Known Data to Unknown Nodes
• Iteratively propogate with adjacent data• Dynamically adjust with ‘hard’ data• Lather, rinse, repeat
= Known data
= Unknown data
A li i
8/7/2019 graphs (by @cdixon and @hunch)
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Applications
Fun with APIs
“netflix predictions
for everything”
e-commerceand mobile
Youzakk, AutomaticDJ
8/7/2019 graphs (by @cdixon and @hunch)
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Since we’re at Google, some more stuff aboutGoogle
8/7/2019 graphs (by @cdixon and @hunch)
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Communications Graphs:How Related are they to Social or Taste Graphs?
My iPhone contacts include some of my friends……but also my plumber, doctor, network administrator, UnitedAirlines and the Chinese restaurant around the corner
A lot of people were surprised that their email contacts were
assumed to be active social contacts
Could We Use Ad Preferences to
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Could We Use Ad Preferences toCold Start Restaurant Recs?
32
hotpot
+
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We know this person likes Classical Music, Yoga, Poetry, and Hiking
33
Hunch would recommend Seafood Mediterranean Greek and Sushi Restaurants
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Hunch would recommend Seafood, Mediterranean, Greek, and Sushi Restaurants
Cross domain data can solve the “Napoleon
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Cross domain data can solve the NapoleonDynamite” problem
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