Window

I dunno, but "SillyGirl739 18/F" Would get it ;)

My guess, is camera trickery. That explains everything.

Just think how easy that would be to fake, assuming you have a willing collection of mates/actors/people who want to be on telly and are willing to make the right 'oh my gawwwwwd' noises.

It's magic, innit ???

He'd better not reveal his secret to chavs, or we'll be having 'em through the double glazing every night.

Glass is the shape of an L rotated through 180degrees, and is slid up to give a hole where the paper's being held up, then slid back into place once the bloke's walked through. The shop and people holding the paper are plants.