Inside vCrd.co's vCards you can set your Facebook, Twitter and Linkedin profiles to be saved inside your vCard. Below are how you can find what your true profile links are for each of these services.
Log into Facebook, then click on your profile picture & name at the top left of the page. Copy the URL out of your browser's address bar.
Log into Twitter, then click the "Me" navigation link. Copy the URL out of your browser's address bar.
Log into Linkedin, then go to Profile -> View Profile. In the middle of that page, you will see a link that looks like the image below. Click that link and then copy the URL out of your browser's address bar.
Don't forget to customize your Linkedin profile URL if you havent already.