Wiktionary
n. 1 The removal of something from its box; an unpacking. 2 (context programming English) Automatical conversion of objects back to value types. vb. (present participle of unbox English)
Wikipedia
Unboxing is the unpacking of new products, especially high tech consumer products, where the process is captured on video and uploaded to the web.
Yahoo Tech places the first Unboxing video to be for the Nokia E61 cellphone in 2006. According to Google Trends, searches for the term "unboxing" began to surface in the final quarter of 2006. Early unboxing videos were focused mainly either on gadgets or fashion items, however once the trend took off unboxing videos were available for, as Yahoo's Deb Amien put it "nearly every thing that is available for purchase" By 2014 the popularity of the videos were such that some companies had been known to upload unboxing videos for their own products, whilst others sent products to uploaders for free.
Some consider the popularity of this practice is due to the ability of showing the product exactly for what it is without any adulteration advertisers usually make around the product. Being able to see what one is getting can contribute to the decision process. Some users have tried to make these unboxings more interesting by doing them in different ways or adding special effects. The most notable of which was an underwater unboxing of a waterproof smartphone.
On YouTube, CD unboxing videos are among the most popular videos on the site.
Usage examples of "unboxing".
Bringing the rest of the pots over and unboxing them made me remember how much fun the two of us used to have when we’d go to auctions and then come home to unpack what we’d bought and enter it on the computer.
After unboxing it, she skimmed over the directions, then loaded it with the first of the packs of film she'd bought.
A large crowd had gathered to watch the riders in their black and scarlet coats saddling up, supervising the unboxing of their horses and grumbling about their hangovers.