This study offers an empirical insight into terrorists’ use of the Internet. Although criminology has previously been quiet on this topic, behavior‐based studies can aid in understanding the interactions between terrorists and their environments. Using a database of 231 US‐based Islamic State terrorists, four important findings are offered: (1) This cohort utilized the Internet heavily for the purposes of both networking with co‐ideologues and learning about their intended activity. (2) There is little reason to believe that these online interactions are replacing offline ones, as has previously been suggested. Rather, terrorists tend to operate in both domains. (3) Online activity seems to be similar across the sample, regardless of the number of co‐offenders or the sophistication of attack. (4) There is reason to believe that using the Internet may be an impediment to terrorists’ success.