The viral and crazy Black Friday videos and Cyber Monday sales make these two days ubiquitously known. But, just one day later is a lesser known, yet arguably more impactful date. This day is Giving Tuesday. Giving Tuesday began as a collaborative project headed by Mashable, the digital media site. Mashable partnered with large companies like Skype and Cisco, as well as well-known charity organizations such as Justin Bieber’s Pencils of Promise and Charity Miles…