When you create a pay per response email campaign, you give up some control on how fast the emails are sent. WhoKnows uses algorithms based on the size and composition of the target audience, the message, and most importantly how many responses you want. WhoKnows will then send out batches of emails and then analyze responses to determine how much to send in the next batch.
Here's an example. If you define a target audience of 100,000 professionals, but your target total replies is only 10 replies. WhoKnows won't send out 100k emails at once because we'd blow up your budget. WhoKnows will send maybe 1000 emails, then see how many responses you get. If you get 10 replies, then you're done! If not, then we analyze the response rate to send out the next batch.