A recent opinion from the U.S. District Court for the Western District of Pennsylvania has renewed the debate over what constitutes sufficient service of Pennsylvania process on an out-of-state defendant via certified mail. A business should not assume that a plaintiff has properly served it just because the plaintiff produces a signed certified mail receipt. Rather, businesses should investigate whether plaintiffs followed the proper procedures for service by certified mail and should research whether the person who signed for the mail was authorized to do so.