ABSTRACT Aims  To assess the profile, utilization patterns, satisfaction and perceived effects among users of electronic cigarettes (‘e‐cigarettes’). Design and Setting  Internet survey in English and French in 2010. Measurements  Online questionnaire. Participants  Visitors of websites and online discussion forums dedicated to e‐cigarettes and to smoking cessation. Findings  There were 3587 participants (70% former tobacco smokers, 61% men, mean age 41 years). The median duration of electronic cigarette use was 3 months, users drew 120 puffs/day and used five refills/day. Almost all (97%) used e‐cigarettes containing nicotine. Daily users spent $33 per month on these products. Most (96%) said the e‐cigarette helped them to quit smoking or reduce their smoking (92%). Reasons for using the e‐cigarette included the perception that it was less toxic than tobacco (84%), to deal with craving for tobacco (79%) and withdrawal symptoms (67%), to quit smoking or avoid relapsing (77%), because it was cheaper than smoking (57%) and to deal with situations where smoking was prohibited (39%). Most ex‐smokers (79%) feared they might relapse to smoking if they stopped using the e‐cigarette. Users of nicotine‐containing e‐cigarettes reported better relief of withdrawal and a greater effect on smoking cessation than those using non‐nicotine e‐cigarettes. Conclusions  E‐cigarettes were used much as people would use nicotine replacement medications: by former smokers to avoid relapse or as an aid to cut down or quit smoking. Further research should evaluate the safety and efficacy of e‐cigarettes for administration of nicotine and other substances, and for quitting and relapse prevention.