The interactive use of visual interface tools has diversified the use of visualisations. This article reviews the relevant aspects of interaction and challenges the sufficiency of traditional evaluation criteria developed for static graphs. Traditionally, the problem for statisticians has been to maintain perceptual discriminability of details, when quantities of data increase. Currently, however, even non-professional users need to integrate qualitatively different kinds of information. The review of task requirements indicates the use of a visual outline: (1) visual tools can facilitate parallel separation of individual data entities and integration of their features and (2) more focused comparisons require visual memory due to eye movements. The article reports psychophysical experiments that measure performance accuracy and response latency conditioned by the above task requirements. The impact of shape and colour on performance interacted with display times; the times were shorter (100ms) or longer (1 s) than the duration of typical gaze fixation. The features of graphs in the experiments were derived from a popular internet service. Thus, we describe methods for evaluating visual components of real services and provide general guidelines for visual design of human-computer interaction.