A profile provider: (i) associates a set of devices (including two or more online devices and possibly a set-top box); and (ii) delivers an advertisement targeted using profile information associated with one of the online devices. The advertisement is presented along with media content. If the media content is viewed using a single-viewer display, then profile information is used that is associated with an online device used to select or receive the media content. If the media content is viewed using a multiple-viewer display, then profile information is used that is associated with an online device used to select, receive, or present the media content or with an online device associated with one or more of those online devices.