I've used Gmail since 2004, and now I have about 3000 Gmail contacts. I don't recognize the vast majority of them and many of my contacts are just email addresses. Over the years I've synced my contacts with every social network and cloud sync service out there and now my address book is a real mess. I only use my address book for personal mail. I have less than 200 people that I actually keep in touch with - I don't exactly know how the other 2800 contacts got there. I sync my Gmail with iCloud, so my iPhone's contact list is a mess too.
Is there some technique, application or service to magically clean up my address book? Perhaps I could delete everyone who I have not sent any email to.