[CrazyStat]

That's how traditional teleprompters work: screen below reflecting off the half-silvered mirror, camera behind.

Many laptop screens don't open completely flat, so that may not work for this particular concept.

[throwaway316943]

The tutorial is already suggesting harvesting a web cam from a laptop, why not just extract the screen instead? Lots of info and equipment out there for repurposing laptop screens.

[gowld]

Flat (really, parallel to ground) doesn't matter -- you just need to adjust the angle of mirror to match.