I wonder if the new Internet age era someone would consider to have a horseshoe on the web site or blog. We all know what horseshoe stands for, a shoe for the horse. After the horses were put into work it was necessary for them to own a shoe, in the shape of the moon.
The use of the worn out horseshoes was also popular in many countries. The tradition to hang the horseshoe above or next to the doorway originated first in Europe (most of Europe), and spread to the Middle-East, and Latin America, and eventually enter Americas. From my experience, many old barns in North America will have a horseshoe if you look closely - an example here.
In most of Europe, the Middle-East and Latin America horseshoes are placed downward or opening down, however, in some parts of Ireland and Britain people believe that the shoes must be upward or 'the luck will run out'. Americans of English and Irish descent prefer to display horseshoes upward; for Germans, Austrians, Italians, Spanish, and Balkans 'it must point down so the luck can pour onto you'. Two different ways, no wrong way. However, most of people were satisfied either way, because since the shoe protects the horse then it must protect the people.
In some countries such as Italy, a horseshoe is nailed by the side of the door and not above. Direction is not important, but some still do point them downward. However, it is important that the horseshoe was worn and discarded by a horse. Meaning that the horseshoe was found on the road or field, and not purchased. In addition, a person entering through the door can touch it.