1. Spotting Trends
The Wisdom of the Few
Xiaolan Sha◦
Daniele Quercia✦
Pietro Michiardi•
Matteo Dell’Amico•

2. Our Work
What are the trends one might be interested in?

3. What Is a Trend
Popular
≠
Trending

4. Who Create Trends
｝｛
Influentials Trend Makers
ED (upload)
BIN
OM ESS
A C OC
PR
Accidental Trend Spotters
(vote)

5. Our Context
SP
Te
E CI
c
De hnol
og
AL
sig
n- y
Co -Sav
ns v
cio y
us

6. Our Context
A core group of users are main content contributors.
9,316 users, 6,395 items and 21,252 votes

7. Traditional
item i
p(u,i) = 1 if u likes i, otherwise 0
user u
Items
ALGORITHM
Recommend
Users
Preference Matrix

8. Our Approach
Trend Spotters
Recommend
Identify Trends
Trends
Trend Makers
User Space Item Space
Trend-aware
Recommendation

9. A Special Few
? Features
｛
Activity
Trend Spotters
Trend Makers
Content
Social Network
SVM
User Space
Geography

10. A Special Few
?
｛
if uploaders are trend makers of any quality
Trends
Logistic
Regression
Item Space if voters are trend spotters - only of high quality

11. Trend-aware
trend i
p(u,i) = 1 if u likes trend i
user u
SVD Recommend
Trends
Trends
Trend Space
Trend-aware
Preference Matrix

12. Our Approach
Trend Spotters
Recommend
Identify Trends
Trends
Trend Makers
User Space Item Space
Trend-aware
Recommendation

13. Baseline
item i p(u,i) = 1 if u likes i and item i is a trend,
otherwise 0
user u
Items
ALGORITHM
Recommend
Users
Preference Matrix

14. Evaluation
Recall(N) = #hits / |T|
Precision(N) = #hits / (N * |T|)

15. Summary
Popular ≠ Trends
Trend Spotters & Makers Exist ! Identify them improve the
recommendation.

16. Spotting Trends: The Wisdom of the Few
Xiaolan Sha, Daniele Quercia, Pietro Michiardi, Matteo Dell’Amico
Thank You!