Politely but very insistently, the television ad asks if you or someone you know experiences nervousness and discomfort in social situations. Of course, you personally neither palpitate nor sweat in public places. But do you have a close and troubled friend who fits that description? Perhaps he or she should consider taking a special pill. Or consider your aging parents. Their energy isn't what it once was, and keeping in touch across time zones is increasingly awkward. Having them on e-mail would be great. Alas, they're stubborn technophobes. You're not confident you can reliably get them online. What should you do?

While these simple scenarios involve provocative personal decisions, they also capture an essential innovation dilemma. When are innovators wiser to target their prospective users' perceived communities of care than the prospective users themselves? Getting people to do something innovative for themselves is one kind of challenge; persuading them to persuade other people to invest in novelty is quite another.