The booster emails can incentivize the participants of your "Tempting Giveaway", "Startup Pre-launch" and "Leaderboard Giveaway" campaigns to keep sharing their unique URL with their friends in order to increase their chances of winning the prizes you offer in the campaign, get earlier access to your product etc.
Automatic booster emails are sent, well, automatically, every few days. You can set this interval from the "Booster emails" step of the campaign wizard. In general, the following rules apply:
The interval between two subsequent mailings can't be less than 5 days. The reason is to protect participants from feeling they receive too many emails from you, which might make some of them make spam reports.
The first booster email is sent X days (however you have set X to be) after the participant joins the campaign and every subsequent email is sent X days after that.
The emails are sent at around the same time of the day as the time the participant first joined the campaign so that people won't get annoying email notifications when they're asleep.
Note: If you choose the manual option, instead, then a "Boost" button will appear in your campaign's dashboard after the equivalent number of days you set in the "Booster emails" step of the campaign wizard ("Email them after X days" section).
Did this answer your questions? Reply to let us know!