= Opt-In Users = GENI opt-in users are those users who knowingly or unknowingly participate or “opt-in” to a GENI experiment, and become part of the slice. * Users may explicitly opt-in to a GENI experiment by choosing to participate in a GENI experiment or use an experimental service running within a GENI slice. For example, a user may opt-in to an experimental email service run by an researchers on the GENI infrastructure by configuring his or her email client to use this service. * Users may be co-opted into a GENE experiment by, for example, having their network traffic directed into a slice by an authorized agent such as their campus network operator. == Resources for Experimenters == If you are running an experiment with opt-in users, you might want to take advantage of these [wiki:TipsForExperimentersWithOptInUsers tips and recommendations].