An analysis of the 2002 SIQSS time-diary data offers support for the displacement theory of time utilization. Time spent on the Internet is found to have a negative relationship with a number of daily activities, especially discretionary activities. Most notably, time spent on the Internet appears to come at the expense of time spent on social activities, hobbies, reading and TV viewing. Time spent on the Internet has a small, but less substantive, impact on time spent on work, childcare, housework and sleep. These predictions are robust to multivariate controls and proportional comparisons.

According to the "functional equivalence" argument that has been applied to the diffusion of earlier communication technologies, one should expect decreases in daily activities that perform the same functions as the Internet. An effective, comprehensive method for testing which activities seem most affected by the Internet is through 24-hour time-diary studies, in which all daily activity is recorded.

When one compares the time diaries of Internet users and nonusers in a combined 1998-2001 national telephone diary study, one finds consistent declines in TV use and sleep times among Internet users, but no consistent declines in reading or other activities. This finding suggests some ways that the Internet may affect some communication activities more than others. This lack of strong changes is a rather different pattern from what seems to have been the case for television, as predicted by the functional-equivalence hypothesis.

This study compared the time use of parent and child IT users with that of parent and child nonusers. The study took advantage of a year 2000 data collection that involved a national sample of 450 dual-income, middle-class families. All family members kept a complete, weekly account of all of their daily activities. The sample thus has the advantage of being restricted to a relatively homogeneous population group in terms of age, family circumstance and life stage.

The major difference found between parent Internet users and nonusers is in terms of the 5+ lower paid work hours of Internet users that offset their 3.5+ weekly hours of Internet use. Parent Internet users slept significantly less, but spent more time reading, radio/music listening and engaging in hobbies. Among children in these households aged 5-18, the major differences between Internet users and nonusers after multivariate adjustments are found in their slightly greater time attending social events and engaging in conversation. Otherwise, the diary figures of Internet users and nonusers, especially for children, are strikingly similar.