You are easily impressed.
There's a metric ton of other products and services that has been doing the exact same thing for over 10 years. From VNC and RemoteDesktop to Citrix and LogMeIn. In fact, LogMeIn's http://join.me is probably the best execution of the idea to date. Still doesn't quite qualify as magic :)
We (the co-founders) are on Olark on the Screenhero website right now, if anyone has any live questions! :)
First, there was VNC, but it didn't let take over the screen. So there came UltraVNC, but it didn't let connect to the target box easily. So there came GoToMyPC, but it relayed everything through its servers. So there came LogMeIn, who used servers to bootstrap sessions and did the rest in p2p fashion. But it was still too generic, so there came something like CrossLoop and made a tech-support oriented screen sharing service. GTMPC further simplified the UX and so did the LMI, but that more of an incremental improvement rather something that would've a new player to bite a part of a market.
So what do you bring?
When you share a screen a long numeric code is provided which you give to the other party. They also have a mode where you can export your own systems and access them when no one is at the console. That only works for Mac and Windows.
Hopefully competition will start heating up. I want to see my desktops on mobile devices and my mobile devices on desktops. I want sound, clipboards and storage. I want a better solutions to screen size disparities.
But you're right, this is a space with lots of potential. X11 could do all this and more already in 1996 one can even connect multiple mice / keyboards; it is sad that this function never really made it into other operating systems, although on the other hand X11 had lots of other issues due to the complex architecture to allow for network sharing of invididual screens.
CRD and VNC viewers I use all support scaling so that solves things when the resolutions aren't too disparate. I can imagine a solution involving scaling and (automatic) panning would work quite well.
> The idea of being able to only share a certain window is fantastic
For that I use Skype which lets you share an arbitrary rectangle. Unfortunately the viewer has no control.
Also I'll probably use this a lot in another project where me and the other guy doing it are really rarely in the same country. Utilizing this, it is much easier to discuss code, layouts, or even point out a weird behaviour of code by sharing the iOS simulator and going through the process that leads to the bug.
Thanks for this fantastic app, I love it.