The demographic and practice-related characteristics of physicians who use social networking websites, portable devices to access the internet, email to communicate with patients, podcasts, widgets, RSS feeds, and blogging were investigated. Logistic regression was used to analyze a survey of US primary care physicians, pediatricians, obstetrician/gynecologists, and dermatologists (N=1750). Reported technology use during the last 6 months ranged from 80.6% using a portable device to access the internet to 12.9% writing a blog. The most consistent predictors of use were being male, being younger, and having teaching hospital privileges. Physician specialty, practice setting, years in practice, average number of patients treated per week, and number of physicians in practice were found to be inconsistently associated or unassociated with use of the technologies examined. Demographic characteristics, rather than practice-related characteristics, were more consistent predictors of physician use of seven internet-based communication technologies with varying levels of uptake.