Something that is so mainstream that pretty much everyone likes it and it becomes lame for that reason.
1. Dude, did you listen to Green Day? That's so lamestream.
2. I didn't want to be lamestream so I started listening to screamo.
by dave "pelirrojo" rogus November 18, 2007
Things that people participate in or go to because they think it will make them look hip.
Rob: Are you going to Lollapalooza on Friday?

Burt: Dude, Lollapalooza is SO Lamestream!
by Burt Maass March 21, 2008
Posers who like something because they think it's cool, or to be "part of the crowd". Lamestreamers are the ones who find out about "cool new music".
I'm always fearful of "lamestreamers" liking my favorite bands. Kings of Leon, Vampire Weekend ARE Lamestream. They are the poster children for Lamestream-ness. Please don't start liking Washed Out.
by ImNoBozo June 30, 2011
What every damn dirty hipster calls people who listen to the bands they like without realizing they fit the type.
Unless you were there when the band formed and jammed for the very first time, you didn't discover them, thus you are a lamestreamer you damn dirty hipster.
by EatMeEatMeRaw July 13, 2013
A term hipsters use to define something that tries to be hipster and fails by still being mainstream.
Hipster One: Did you see that girl wearing fake glasses?
Hipster Two: Yeah, she's being lamestream.
by IceOfWaterflock May 29, 2013
All major media companies except for FOX.

Sarah Palin needed a new attack word against the mainstream MSM media when she got hired by one of the world's largest mainstream media companies.
In recent news, some people say Glenn Beck is reported to be the most honest man in broadcasting, and you won't hear that reported by the lamestream media. This is Sarah Palin, reporting for FOX News.
by Knot O'Really February 12, 2010