I really wish facebook could help me manage the outer reaches of my social sphere—those I contact infrequently, whom I care about, but am not in constant commun

I really wish facebook could help me manage the outer reaches of my social sphere—those I contact infrequently, whom I care about, but am not in constant communication. Something that would prod me to send a message or something to an old friend I hadn't remembered to email in the past month or so.