We believe there
are many ways to
increase the coherence,
of systems, and
this quest has
September + October 2012
These local fixes maintain or raise the level of the
trade-off curve. Now consider
some examples of systemwide
changes in interaction, which
can have—as we said earlier—a
profound impact on moving to
higher trade-off curves. Their
diversity suggests that many
more will be forthcoming.
Design languages. Tools for supporting domain-specific design
are often stuck trying to find the
right balance between generality and particularity in providing ways to describe the domain.
Designers of the Trillium design
environment for photocopier user
interfaces saw this tension as due
to forcing all design into a single
language (complete coherence) [ 4].
Instead, the language of description itself was recognized as part
of the ongoing design activity,
and therefore was made a part
of Trillium’s subject matter. New
concepts were created for new
product families, new products,
and new designs (very responsive).
For balance, coherence was maintained socially, through the ability
to easily share and extend design
concepts, daily use of email, and
Allowing language to evolve in
use is a powerful means of managing the trade-off curve for a
growing space of products.
Web search. Early navigation of
the Internet was supported by
hand-built “maps,” such as the
old Yahoo catalog. But the rapid
growth and change of the Internet
quickly made comprehensive maps
impossible, while early search
utilities were not good enough to
replace human mapping.
Larry Page and Sergei Brin
solved this problem with the
PageRank algorithm, which aggre-
gates the local knowledge implicit
in the network of references
between pages. Since then Google
and others have evolved increas-
ingly sophisticated ways to aggre-
gate local knowledge.