From the begining of the course we have been implicitly assessing issues of efficiency towards effectiveness, or heading to their recognition in the context of modelling and design. In previous post some reflections already expressed concerns about these concepts. Efficiency has to do with speed and practicalities, more on the logistic side of a strategy (design), whereas effectiveness is a descriptive quality of an outcome that is well balanced and stable: a goal is acomplished as fast as possible, within the capacity of the device combined with the abilities of the users (quantifiable, as we have learned in past modules, and reminded to in this one). Not only there is a limit to efficiency, where increments are no longer possible, that is 100%; but also there are many factors that play important roles in proposing a good interactive/interface design. Kiera´s article empasizes again the importance of trade-offs and introduces the notion that even when a system does not "seem" to be too efficient, it must enable learning through experience, so the user who is not familiar with the methodology can gain competence with a continuous use. I believe tha is is the risk that every innovation has to run when demand for it does not match an excess of supply for newer or more sophisticated products, in general.Once again the supporting literature is illustrative onhow to quantifiy and calculate numeracally human behaviour. These indicators are what information science is all about, but require for their interpretation a very serious interdisciplinary qualitative expertise and approach. None of the existing models or tools is fail proof, or can succeed to be comprehensive. Sometimes it may seem a waste to invest so much time, considerations and effort designing systems and objects that might be obsolete in very short time. Duration has to be an element that nowadays should influence design, because never before have objects (including interfaces; virtual and analogous; interactive or not; on any field) been so short lasting. One could take any example, for instance on computer applications or software. They are constantly changing, and not necessarily because of efficiency (granted that efficiency is not everything, but assuming that usability is a multifaceted feature). Pinterest just introduced a "new" capacity to "help" people collect and access information about places, systematically. This mapping possibility could be more interactive, but this tweak is not a very welcome facility for frequent pinners. Pinterest is useful and efficient the exact way it is and needs not to begin complicating its use. It is hard not to feel that one spends too much time on it already, and these sudden offers are a wake up call for many of us who realize the more they offer they more one gets hooked, and as a resut would spend (unnecessarily) a nincreased amount of time on their site. Efficiency on what is not necesary is also innefficient, in other words.