Blog is short for "web log" a popular way to journal your life online for everyone to read.

When you're with someone and something blog-worthy happens, then you say "Blog It" to them. It is a suggestion for the other person to note the incident in their blog.

An expression of distaste for an event.

Basically, a sarcastic, rude way of saying, "No thanks, I do not wish to participate, but tell me how it was."

Quick and easy way of verbally owning emo kids, whiny bitches and/or just about anyone who complains so much, they make you want to choke a small animal then shove it down their throats. Can be used for all degrees of whining and in conjunction with other anti-emo send-offs like "cry more", "\cry" and "don't cry, emo kid".