Definition
Indicating a change of subject to unimportant topics.
How People Actually Use It
When people says or do something outdated (Such as putting an L on their forehead and saying you go girl/guy, ugh I hate that phrase) you can say, "Hows the weather 7 years ago"
"Some pompous chick: "You go boyfriend!" You: Hows the weather 7 years ago? Some pompous chick: ....YOU SUCK Some pompous chick just got her ego curb stomped, Steven Segall style."
Source: Urban Dictionary