Hi Vireya,
You can send the quilt block to someone who doesn't have the application and they would receive a notice/message telling them that you sent a quilt block. They would have to decide if they want Quilt Block Party or not. If they choose to install the application on their page then they will get to see the quilt block you sent and your message, if you included one. If they do not want the application, then there is no way for the application to access their profile and display the quilt block.
While this seems to be a bother that you can't just send quilt blocks to any friend you wish, it is actually a good thing. If there were no safety checks like this then people could conceivably create malicious applications that would simply install themselves into peoples' profiles without permission, steal information, delete legitimate stuff, post things you may not want on your page, and cause all sorts of problems. This way, both users and legitimate applications are protected.
Try sending quilt blocks to a few friends and some of them will likely install the application and some won't. You can also use Quilt Block Party to send invitations to install the app or even just a direct personal message through Facebook to peoples' inboxes telling them you think they might like it.
Hope this helps!
^_^ laura
http://quilting-diva.blogspot.com