Invite them to... not use it? That seems like a solid way to turn people off from using a service, not a way get them excited about it.
I would be _far_ more likely to tell my friends about the product if I could actually use it and be able to vouch for it (as I have with the mobile version of TextSecure/Signal).
Forcing me to get my friends to visit a page where they will find out about an application they can't even use is just annoying.