Fig.: today's idiomatic meaning refers to a person of any age who is the perfect example of a specific quality, opinion, cause or type of person, thus becoming a symbol and an example for other people

The famous French soccer player has become the “poster boy” for a whole generation of French-born youths of North African extraction

Il famoso calciatore francese è diventato l'uomo immagine per un'intera generazione di giovani francesi di estrazione nord-africana

“This is Lori, my poster girl” “What do you mean?” “Well, one day she came to our bridge club asking to play; we played together and in just two years we went to the Nationals!”

“Ti presento Lori, la mia donna immagine” “E cioè?” “Un giorno è venuta al nostro circolo del bridge chiedendo se poteva giocare; abbiamo giocato insieme e dopo soli due anni ci siamo qualificati per la finale del campionato nazionale!”

The owner of our company built his huge fortune and his successful career from nothing. He really is the “poster person” for the American Dream

Il nostro titolare ha costruito la sua enorme fortuna e la sua fortunatissima carriera dal niente, diventando così un vero testimonial del Sogno Americano

In origin, a “poster child” was usually a child afflicted by some disease or deformity whose picture was used on a poster for a charitable organization. Although this older definition is still around, today's new, idiomatic meaning of “poster boy” or “poster girl” – referring to adults linked to a topic that captures public interest – is getting more and more popular.