I take this to mean that any iPhone app can download your address book to their servers? What. The. Hell! Apple?
Upon inspecting closer, I noticed that my entire address book (including full names, emails and phone numbers) was being sent as a plist to Path. Now I don’t remember having given permission to Path to access my address book and send its contents to its servers, so I created a completely new “Path” and repeated the experiment and I got the same result - my address book was in Path’s hands.