  Understanding human dynamics is of major scientific and practical importance
and can be increasingly addressed in a quantitative fashion thanks to
electronic records capturing various human activity patterns. The authors of
Ref. [1] revisit the datasets studied in Ref. [2], making four technical
observations. Some of the observations of Ref. [1] are based on the authors'
unfamiliarity with the details of the data collection process and have little
relevance to the findings of Ref. [2] and others are resolved in quantitative
fashion by other authors [3].
