Recently, Jevgeni asked me how much code I was able to share between my projects by using a Portable Library. He is contemplating building a Windows Phone and a Windows Store app and wants to create a Portable Library for sharing common code.
So I decided to get some numbers based on my new app code which is going to (hopefully) reach Windows Store soon.
The app is not 100% ready yet, so I might add few lines of code but at the moment it turns out I placed more than 70% of my code in a Portable Library.
However, I invested quite a lot into having such a structure as I plan to release a Windows Phone app around the same core.