We ran experiments to study the role of email subject lines on improving response rates to Web surveys in nine countries. In the first study (US and Canada) subjects received an email invitation and two email reminders; we randomly assigned potential respondents to receive different email subject lines for each. For the initial invitation, the subject line was either a question (―Would you like to provide your feedback?‖) or a polite request (―Please provide your feedback‖). The polite request received 21% more responses. For the first reminder, the subject line either appealed to personal interests by reminding them of the incentive (―Provide feedback & receive a mug‖) or played on the bandwagon effect (―Join other advertisers in providing feedback‖). The incentive reminder was 94% more effective. The final reminder either provided a deadline for completing the survey or did not; including a deadline in the subject line was 42% more effective. We replicated the experiment in Europe, with modifications: no incentive was offered, and subjects were randomized to condition for each email. The body of the email invitation was kept the same across conditions--only the subject line differed. As in North America, the polite request outperformed the question, improving the response rate by 21%. The second experiment tested the ‗bandwagon‘ wording against a strong directive: Provide your feedback on...; the directive improved RR by 18%, a statistically significant difference for 5 of the 7 countries. Finally, in Europe we did not see a difference between a reminder that included a deadline and one that did not; we hypothesize the lack of incentive lead to a lack of urgency to complete the survey on time. We will discuss these findings in light of the literature on email subject lines and provide suggestions for using subject lines to improve RR to Web surveys.