I really like your idea and its pretty self explanatory once you watch the demo. I also like that your demo is somehow hidden - you can't just watch it, you just use the product for the first time and learn it. Don't change it - it's fun and makes for a 'wow' moment.

After some time I started to wonder why I would need a QR... well... QR must be pairing a unique computer/ip/browser (?) with the phone, right? Nice.

I would not bother to add too much explanations on the main page - now its a little mistery and I like that demo is 'hidden' (see above). Also, dont add that both presentation machine and phone must be connected to the internet - it is evident and even if it is not, well, people will figure it out.

Edit: As others mentioned, need for network connection introduces some serious uncertainty. I just get it and would never take a plane (slide 5?) without a copy of my presentation on me.

Have not been presenting for quite a long time, but will surely give it a go when I do.

We recommend Scan for (iPhone) or Google Goggles for (Android). You might want to fix ()'s: (for iPhone) (for Android)

Thumbnails for slides on the phone must be your next feature, am I right?