關於「Postcrossing ID」標籤，搜尋引擎有相關的訊息討論：

Explore countries and territories in Postcrossingwww.postcrossing.com › explore › countriesLinks to the first postcard from different countriescommunity.postcrossing.com › ... › General TopicsPostcrossing - 維基百科，自由的百科全書zh.wikipedia.org › zh-hant › Postcrossing和全世界交流明信片的Postcros