gap between SMS and MIM.

when necessary. After we developed the UI of mMessenger, we conducted usability tests and focus groups, both of which confirmed the effectiveness of the new UI.

• Figure 4. Data consolidation: the Affinity Diagram.

The new messaging tool is “mMessenger”—it combines the strengths of SMS and MIM. Imagine a 25-year-old “not to talk” named Tracey. Unlike with existing MIM solutions, Tracey does not have to register a screen name or password for initial use, nor does she need to find out her friends’ screen names to add them to her buddy list. mMessenger takes advantage of a standard SMS feature, namely, telephone-number-based communication. Tracey can use mMessenger instantly without any registration hassle, since her telephone number is her ID. She can send messages to anyone whose telephone number is in her cellphone contact list without the cumbersome process of adding a buddy.

• Figure 5. User modeling: examples of personas.

[2] IDEA; http://www. idsa.org/IDEA_Awards/ gallery/2008/ award_details. asp?ID=35918411/

where instant messaging is just
a mouse click away. However,
they still want to communi-
cate with a small number of
friends using their cell phones.
They prefer to have conversa-
tions that consist of only two
or three messages, and SMS
group conversations give them
a headache.

January + February 2010

Innovative Mobile User
Interface and Service Strategies
Based on our research, the
Affinity Diagram results, and
the needs and pain points
of our primary persona, we
developed a new conversa-
tional messaging tool that
consolidates various types of
conversations. These include
both short-interval (intensive)
and long-interval (sporadic)
messaging. The tool fills the

Users with mMessenger on their phones can still communicate with standard SMS handsets, since the mMessenger server automatically transforms the message into SMS. Customers can simultaneously send and receive messages with two or three friends, individually. In addition, with a threaded messaging format— considered novel at that time (Apple announced its threaded SMS format for the iPhone in 2007)—they can read the conversation conveniently.

On the business side, the cli-
ent (SK Telecom) was very satis-
fied with the new mMessenger
user interface. SK Telecom has
high hopes for its new services-
based business model, which
is now a key focus area. Since
the mMessenger commercial
launch in 2006, the number
of users has been increas-
ing despite the fact that SK
Telecom does not advertise
this service for the mass mar-
ket. pxd recommended that SK
Telecom not spend money on
advertising until the number of
users reached a critical mass; if
network services such as MIM
are over-advertised, early users
will be disappointed due to
the paucity of other users with
whom they can talk. After they
have been disappointed once, it
is very difficult to change their
attitude.
mMessenger’s user interface
was recognized internationally;
in 2008 it was nominated for
the IDEA Award in the interac-
tive product experiences cat-
egory [2] and short-listed for the
Global Messaging Award in the
user experience category [3].

[3] Global Messaging Award; h ttp:// www.160characters.org/ pages php?action= vie w&pid=53/

interactions

Our research suggests that a user like Tracey encounters a conflict: She does not want to be tied up in a conversation, but she does need to communicate effectively. The design of mMessenger solves this problem. The user can send a one-way message as well as engage in two-way conversation

Korean Handset Manufacturers
and Telecommunications
Companies
As demonstrated in the case
of mMessenger, user research
is the key in choosing not only
the right user interface design
but also the right strategy.
Stakeholders in major Korean
mobile companies such as
Samsung and LG Electronics