I recall you speaking about this when we chatted one time. The terminology that I think works for these type of approaches is Opportunity versus Threat based sales. this applies to all types of selling and not just software.

IIRC you mentioned your experiences trying to recruit people for facebook in the early days. The “this is a great tool you should join” or opportunity based sell didn’t work to well. However when the approach was changed to “everybody is already on facebook you don’t know what your missing” more of a threat based approach, then sign ups increased.