Could someone please explain to me what Boxing Day is and the significance of it? Thank you.

A quick search came up with this site
Urban Legends Reference Pages Holidays (Boxing Day)
Andy (++)

Anybody who has ever worked retail can tell you what boxing day is. It's the day you try to rebox all the items that people returned after Christmas.

Would love to know too... the site isn't working..

One theory about the origins of Boxing Day is that the day after Christmas was traditionally when church poor boxes were opened, and the contents were then distributed among the needy of the Parish.

Hey all,
got this from Wikipedia:
Centuries ago, merchants would present their servants food and fruits as a form of Yuletide tip. Naturally, the gifts of food and fruit were packed in boxes, hence the term "Boxing Day".
In feudal times, Christmas was a reason for a gathering of extended families. All the serfs would gather their families in the manor of their lord, which made it easier for the lord of the estate to hand out annual stipends to the serfs.
After all the Christmas parties on December 25, the lord of the estate would give practical goods such as cloth, grains, and tools to the serfs who lived on his land. Each family would get a box full of such goods the day after Christmas. Under this explanation, there was nothing voluntary about this transaction; the lord of the manor was obligated to supply these goods. Because of the boxes being given out, the day was called Boxing Day.
In Britain many years ago, it was common practice for the servants to carry boxes to their employers when they arrived for their day's work on the day after Christmas (December 26). Their employers would then put coins in the boxes as special end-of-year gifts. This can be compared with the modern day concept of Christmas bonuses. The servants carried boxes for the coins, hence the name Boxing Day.
In churches, it was traditional to open the church's donation box on Christmas day, and the money in the donation box was to be distributed to the poorer or lower class citizens on the next day. In this case, the "box" in "Boxing Day" comes from that one gigantic lockbox in which the donations were left.
In Britain because many servants had to work for their employers on Christmas day they would instead open their presents (i.e., boxes) the next day, which therefore became known as Boxing Day.
Cheers,Shay

In Canada its a glorified "Holiday" which is for the stores. They mark down a few items and people flock to buy said items.