Walls of Wishes aren't strictly an Italian concept. One of the earliest known references actually goes back to the 18th century Israel. Where Rabbi's would instruct the destitute to write their prayers on slips of paper and place them in the cracks of the Western Wall, the Jewish Holy site in the Old City of Jerusalem. It is believed that there is Divine Presence in the Western Wall, therefore to this day millions leave their prayers in every language in the wall's cracks each year.
In Turkey many Christians will make a pilgrimage to the The House of the Virgin Mary near ancient Ephesus in Kusadasi, Izmir province. It is believed the Apostle John brought her there for protection after the crucifixion of Jesus. The site is considered Holy for Christians and visitors to the wall will often leave wishes written on just about anything you could imagine- pieces of clothing, napkins, old tickets, and the like. A bit different than the "ex votos" concept which practices gratitude for wishes granted. Visitors reportedly ask for the usual suspects- health, happiness, money, and of course love. A good dutiful husband or wife is a most common request, along with the occasional red Corvette. Hey, people will always try.
In Japan a celebration called Tanabata falls on July 7th. 7/7 get it? Tanabata is celebrated with food and joyous festivities, but the most important of all is the ritual of tanzaku or writing wishes on colorful strips of paper and tying them to trees.
In Japan as well as other parts of Asia- China, India, Taiwan, and Thailand, sky lanterns carrying written wishes and messages to God are released during certain holidays. In India during the Christmas season the lanterns represent the Star of Bethlehem and prayers for the coming new year are sent into the sky.
In Seattle there is a far more crass and modernized version- Pike Place Market's "Bubblegum Alley" where it is said one should chew some gum, then make a wish and add it to the wall. I'm making a face right now, you can't see it, but it's there. The thought is nice...I guess, but I'm a bit leery of walking down that alley. Seems like a sticky situation to me. Tuberculosis waiting to happen, but to each his own, I won't be a hater.
Wishes and prayers, and gratitude for divine intervention all reside in the spirit of hope, which is a beautiful thing in all of its manifestations around the world...still not keen on the gum wall.