resources, since they could simply be hidden by
switching to another activity. Activities within ABC
allow for additional ways by which to organize work,
on top of traditional organizational strategies. Systems such as co-ActivityManager do not impose a formal activity model on users but rather provide them
with an additional activity abstraction that can be
used to organize and structure work on their desktop.
Activities were created both up front and retrospectively as activities evolve over time. Post hoc activity
creation usually occurs when an ongoing activity
context becomes too large and is split into multiple
activities. Users appropriate activities differently,
including differences in intention and duration.
Activities were created for short undefined ad hoc
work, to long-running collaborative projects.
There is a learning curve associated with using activ-
ities. Initially most users are reluctant to create too
many activities as they see the effort of doing so
greater than the estimated benefits. However, after
having used an ABC system over longer periods of
time and having experienced the advantages first
hand, users start to create activities even for smaller
one-hour tasks. Structuring work within the context
of activities becomes especially interesting once
more elaborate work needs to be done. All users who
were confronted with multitasking on a daily basis
preferred ABC over the traditional approach.
Users reported that the process of constructing and
sharing activities with each other helped them
reflect on their work and that of their collaborators.
Activity management and sharing thus increases the
awareness of users about ongoing processes within
the working context.
Within a collaborative setting, users found that
sharing information and setting up collaborative
processes in the context of an activity significantly
helped them manage ongoing work. Users would, for
example, asynchronously share an activity (which in
a desktop configuration contained files and contacts)
with other users to create a shared starting point for
a collaborative project. After this initial sharing
process, the scope and definition of the activity can
be changed and appropriated by all users depending
on their role inside the project. Communication and
collaboration channels such as logs, chat windows,
Figure 4. RecticularSpaces.
This figure (Bardram et al. 2012) depicts an activity-based smart-space setup, comprising large wall-based displays, horizontal tabletop displays, laptops, and tablet computers that all run ReticUI, the unified user interface.