1. On the Central Role of Mailing
Lists: An Exploratory Study
Emad Shiahb
Nicolas Bettenburg
Bram Adams
Ahmed E. Hassan

2. The Central Role of Mailing Lists
Open Source developers are distributed ….
... they communicate through mailing lists
… this makes mailing lists a rich data source that
we can leverage

3. The Central Role of Mailing Lists

4. What we Studied…
Developers
External
Factors
Source
Code
Q4. Competition?Q1. Communication
style?
Q2. Stability?
Q3. Code changes vs.
Mailing list activity?

5. Mailing Lists Studied
Case study using 22 different
GNOME projects

6. Participant Message Contribution
Question 1

7. 40%
60%
Participant Message Contribution
Divided participants into 2 groups:
Dominant group
(Top 10% contributors)
Casual group
(The rest of contributors)

8. 2%
82%
16%
Distribution of Participation in
Threads
Dominant only
Dominant and Casual
Casual only

9. Participant Message Contribution
Question 1
Answer 1

10. Stability of Participants
Question 2

11. Stability of Dominant Group is
Important!
2%
82%
16%Dominant Only
Dominant and Casual
Casual Only
Dominant group are involved in 98% of threads

12. Stability of Participants
Cosine Distance (CD) to measure participant stability over time
CD = 1 0 < CD < 1 CD = 0

13. Stability of Participants
Cosine
Distance
Casual
Time
DominantAvg. = 0.69
Avg. = 0.15
0

14. Stability of Participants
Question 2
Answer 2

15. Mailing List and Source Code
Activity
Question 3

16. Mailing List and Source Code
Activity
Code Activity (CA) = Lines added + Lines Deleted
+ Lines modified
Mailing List Activity = No. of messages posted

17. Mailing List and Source Code
Activity
76.0

18. Type of Source Code Change and
Mailing List Activity
Divide the code changes into the 3 categories:
1. Additions
2. Removes
3. Modifications
… and measure correlation with Mailing List activity ….

19. Type of Source Code Change and
Mailing List Activity
Associate words to type of Code changes
“new features”
“feature request”
Additions
“bug”
“patch”
“testing”
“maintain”
Modifications

20. Type of Source Code Change and
Mailing List Activity
Additions terms mentioned 57% time more in
Evolution compared to Nautilus
Modifications terms were mentioned in 75% more
messages in Nautilus compared to Evolution

21. Mailing List and Source Code
Activity
Question 3
Answer 3

22. Effect of External Factors on
Mailing List Activity
Question 4

23. Effect of External Factors on
Mailing List Activity

24. Effect of External Factors on
Mailing List Activity
Quantitative study: measure the occurrence of competing
mailing clients to Evolution

25. Effect of External Factors on
Mailing List Activity
Qualitative study: study mailing lists content

26. Effect of External Factors on
Mailing List Activity
Question 4
Answer 4

27. The Central Role of Mailing Lists