The purpose of the Like button is to enable you to share stuff back to Facebook when you click on it. We anonymize all logging data collected as a byproduct of

The purpose of the Like button is to enable you to share stuff back to Facebook when you click on it. We anonymize all logging data collected as a byproduct of serving the Like button and other social plugins within 90 days of their collection. See https://www.facebook.com/help/?faq=186325668085084 https://www.facebook.com/help/?faq=186325668085084. Bret Taylor CTO, Facebook