What is Lamestream?
1.
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.
See
2.
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!
See