Store obsolete/historical contact details with Soocial, but don't sync them

I think it would be great if one could make some contact details as obsolete (possibly adding a time range indicating when it was valid). Primarily this would be useful for email addresses and phone numbers, but I could see a use also for postal addresses, company names, positions, etc. I would normally only want the most recent info to be synced to my contacts, but the history could be useful when trying to find old contacts, or match old contacts with new information.
Is this something you have been considering?
Time stamping last "manual" validation or update of a contact would also improve the process of maintaining the address book.