Since the internet became popular, analysts have wondered about the relationship between email and other means of social contact. Some studies test the replacement hypothesis by examining whether the frequency of email messages sent or received corresponds to decreases (or even increases) in the frequency of in-person or telephone contact.¹⁶ Other studies test this hypothesis by measuring time spent online and time spent on other social activities.¹⁷ Results from both types of studies have been consistent: The internet does not reduce in-person or telephone contact, or any other form of social activity; it replaces only sleeping or TV watching.

This study examines this issue in a different way. Instead of looking for associations between the frequency or duration of email contact and in-person (or phone) contact, this study looks for associations between the percentages of social ties contacted through various media. If the replacement hypothesis holds true, we would expect that high percentages of social ties contacted by email would be associated with low percentages of social ties contacted through other communication media. This survey has the further advantage of being able to test the replacement hypothesis for core ties and significant ties. For example, Caroline Haythornthwaite and Barry Wellman (1998) found that core ties rely on multiple modes of contact, while significant ties rely on only one or two. By separating core ties from significant ties, we can take into account the strength of the tie when assessing the kinds of communication media used.