How 'Giving Tuesday' ushers in the holidays' charitable spirit

Volunteers serve free Thanksgiving meals in Los Angeles.

(CNN)For decades now, millions of Americans have embraced the day-after-Thanksgiving shopping bonanza known as "Black Friday." Then came "Cyber Monday," online retailers' chance to cash in on the holiday buying frenzy.

Now consumers are being urged to open their wallets for "Giving Tuesday" (sometimes written #GivingTuesday), a day to raise funds for charitable causes.
Giving Tuesday started in 2012 by the 92nd Street Y and the Unit