Spam by definition means 'irrelevant messages sent over the internet' but in the context of teens and social media it basically refers to posting or commenting heaps of stuff, whether it be a spamming of emojis, random words or letters, a particular phrase... Just something that gets said or posted way more times than necessary.
This Christmas Carol is "God Rest Ye Merry Gentlemen".
The full verse is as follows:
God rest ye merry gentlemen, let nothing you dismay, hey
Remember Christ ,our savior was born on Christmas Day
To save us all from Satan's power when we were gone astray
Huron, Ontario, Michigan, Erie, Superior
Because the gupta empire started trading and had more resources than the maury an empire did