BuddyPress.org

@minniwelt

Brajesh Singh at BuddyDev.com has a plugin to do just that: http://buddydev.com/buddypress/buddypress-recent-profile-visitors-plugin/

It’s a premium plugin, so you’d have to sign up as a member of his site to get it (membership = $30/3 months). The fee is worth every penny though: you’ll find a LOT of other useful plugins.