core team
committers
active developer
Peripheral developer
active user
Passive user

• Figure 1. The Onion Model of Community Structure in Open Source

hci core team
usability
designers
usability
Evaluators
human level
decisions
non-technical
users
technical
users
technical level
technical core team
committers
contributors

• Figure 2. Stacked-Onion Model with Additional Core HCI Level May + June 2010

interactions
[ 2] Antikainen, M.,
Aaltonen, T., Vaisanen,
J., Feller, J., Fitzgerald,
B., Scacchi, W. and Silitti,
A. “The Role of Trust in
OSS Communities—A
Case Linux Kernel com-
munity.” In Open Source
Development, Adoption
and Innovation, 223–228.
New York: Springer,
2007.

common coordination problems
during disasters. This Sri Lankan
open source community came
together after the 2004 Indian
Ocean tsunami; distributing
clothing and food to victims was
very difficult because the govern-
ment lacked an infrastructure for
pulling together the magnitude
of donations. No communications
or tracking structure existed.
The community is now sustain-
able and has won an open source
community-choice award. Other
examples of software for those in
need include a microfinance sys-
tem, called Mifos, which boosts
economic development in third-
world countries. And for those
who care deeply about under-
funded schools that can’t afford
IT systems, the open source proj-
ect School Tool provides a school
information system.