How Do Developers Blog?

An Exploratory Study

Dennis Pagano, Technische Universität München

Walid Maalej, Technische Universität München

Integrating Social Media in Software Development

Executive Summary

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• We analyzed blogging

frequency, post

content, and commit

messages in 4 open

source communities

• Blog posts exhibit

recurrent usage

patterns and

common topics

• Relationship between

developers’ blogging

and committing

behavior

1 2

Outline

1 Motivation

2 Research Setting

3 Research Results

4 Summary

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Motivation

• Many software developers publish information related

to their work in blogs

• We do not know how they blog and what they blog

• We also do not understand the connection to

“conventional” development activities

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Towards empirical framework on the role of blogs

and other social media in software engineering

Outline

1 Motivation

2 Research Setting

3 Research Results

4 Summary

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Research Questions

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•How often do committers and other bloggers post?

• What are typical elements in a post?

• Which topics do developers blog about?

• How popular are these topics across the projects?

• Are there publishing patterns in developers’ workflows?

• Is there a semantic relationship between work performed

and information blogged?

1. Blog Usage

2. Blog Content

3. Blog Integration

Research Method

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Collected Data Sets

Eclipse GNOME PostgreSQL Python

# posts 10,333 18,323 2,691 18,660

# bloggers 328 342 95 405

# commits 239,659 252,831 30,745 45,116

# committers 467 2,294 34 178

# blogging committers 93 250 12 34

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Outline

1 Motivation

2 Research Setting

3 Research Results

4 Summary

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Blog Usage: Publishing Frequency

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• Mean time between successive posts within a

community is about 8.1 hours

• Committersblog on average more frequently

(every 26 days) than other bloggers (every 28 days)

• Committers use blogs for longer time periods (about

2.2 years) than other bloggers (about 1.6 years)

Blog Usage: Post Structure

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• Posts comprise 150 words on average

• 95% are shorter than 1,000 words

• 1.8% of posts contain source code paragraphs

• 80% of posts contain links

– Committers include more links to Wikis (11%) than other

bloggers (8%)

– Committers more frequently link to other blogs (28%) than

other bloggers (25%)

• 29% of posts contain images

– Committers post more screenshots (22%) than other

bloggers (18%)

Findings on Blog Usage

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1Regular social activities in the studied open

source communities

2Posts are less frequent than commit messages

but comprise more content

3Posts rarely contain source code, but

frequently high level information and images

4Committers reuse more knowledge than other

bloggers

radio, listen,

player, sync, song,

music, play, ipod,

album, artist, band

radio, listen,

player, sync, song,

music, play, ipod,

album, artist, band

radio, listen,

player, sync, song,

music, play, ipod,

album, artist, band

radio, listen,

player, sync, song,

music, play, ipod,

album, artist, band

radio, listen,

player, sync, song,

music, play, ipod,

album, artist, band

radio, listen,

player, sync, song,

music, play, ipod,

album, artist, band

Method Used to Analyze Blog Content

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Set of words

per community

Common topic

labels

Topic

category

cache, memory,

perform, high,

quality, limit,

secure, cost

Functional

requirements &

domain concepts

Non-functional

requirements

Requirements

radio, listen,

player, sync, song,

music, play, ipod,

album, artist, band

Popular Topics Identified in Blogs

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# Topic description Popularity Examples of influential words

1functional requirements &

domain concepts42.2%

radio, listen, player, sync, song,

music, play, ipod, album, artist, band

2 community& contributions 37.7%people, community, contribute,

group, help, news, post, comment

3API usage & project

documentation30.0%

wiki, write, project, api, document,

use, review, text, output

... ... ... ...

15 source code 14.7%void, new, import, public, final, string,

class, return, private, true

... ... ... ...

23 continuous integration 2.5%resource, test, source, build,

configure, hudson, project, generate

Topic Categories Identified in Blogs

# Category Popularity Example Topics

1 Requirements 51%

functional requirements &

domain concepts, non-

functional requirements

2 Community 45%community & contributions,

conferences

... ... ... ...

6 Implementation 29% source code, solution concepts

... ... ... ...

10 Business 15% licensing

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Findings on Blog Content

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1 More than half of all posts discuss requirements

2

3

Source code and technical content is less

popular

4

Blogs comprise more high-level than low-level

concepts

Community-related topics are orthogonal to

other topics

Blog Integration

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Categories of Commits Before Blog Posts:

Blog Integration Results

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• Most blog posts occur after corrective commits

(~36.5%), least after management commits (~19%)

• Conversely blog posts are more likely after

corrective (2.6%) or management (2.3%) commits

• 15.5% of posts included information previously

described in commit messages

• Dependency between commit messages and blog

posts decreases with increasing time in-between

Findings on Blog Integration

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1Bug fixes and management activities are

frequently shared with all stakeholders in a

software community

2Developers are more likely to publish

information about their recent activities than

about old activities

Outline

1 Motivation

2 Research Setting

3 Research Results

4 Summary

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Summary of the Talk

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• Integration of

blogging

(social)

activities

• Tools for

knowledge

reuse and

topic

annotation in

blogs

Blog

Usage

• Blogging is a regular social activity

• High level information(screenshots) and

knowledge reuse (links)

• Short documentations, tutorials, howtos

Blog

Content

• High-level topics like requirements are

predominant

• Low-level topics like source code are less

popular

Blog

Integration

• Most posts occur after corrective or

management commits

• Developers use blogs to elaborate recent

commit messages

Feedback, Questions, Suggestions and

Collaboration are Welcome!

Pagano, Maalej, May 2011 How Do Developers Blog? – MSR 2011 22

Dennis Pagano

TUM

pagano@cs.tum.edu

Walid Maalej

TUM

maalejw@cs.tum.edu

BACKUPS

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Blog Content – Most Popular Topics

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Eclipse GNOME PostgreSQL Python

functional

requirements & domain

concepts (47%)

community &

contributions (36%)

functional

requirements & domain

concepts (47%)

API usage & project

documentation (50%)

community &

contributions (33%)

functional

requirements & domain

concepts (33%)

non-functional

requirements (40%)

functional

requirements & domain

concepts (42%)

architecture &

packages (31%)

user interface & user

interaction (32%)

community &

contributions (39%)

community &

contributions (42%)

target platform (26%)architecture &

packages (32%)

release management &

announcements (38%)

deployment &

dependencies (36%)

solution concepts &

technology (26%)

development activities

(31%)conferences (25%)

architecture &

packages (36%)

Blog Integration

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Frequencies of Commit Categories:

Blog Integration

Blogging Probability after Commits

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Commit type Eclipse GNOME PostgreSQL Python

Corrective

Engineering1.49% 2.67% 2.17% 4.20%

Forward

Engineering1.35% 1.64% 1.16% 2.81%

Management 0.90% 2.95% 2.46% 2.79%

Re-engineering 1.13% 1.95% 0.99% 2.87%

Blog Integration

Time Dependencies between Blogs and Commits

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