If linking the contact doesn't post all of the information onto Facebook it's OK, but I try not to post much of my info onto Facebook due to identity theft etc, and because I don't like to reveal information used for marketing profiling to social media services.
I know that it's a Facebook contact, because most of the details have a little blue "f" on, whereas there's the contact I set up for me with much more detailed information on my iPad. It's just irritating to have two separate contacts for me appearing now!
Thinking about it, if I combined other people's contacts, it wouldn't change their details on Facebook, but I'm concerned that I might have be giving Facebook the right to use all the information on my combined contact.
Sorry if this is an FAQ or has been answered before - I arrived from the apple support site after checking a couple of relevant troubleshooting lists, but the system hasn't yet asked me if my questions are similar to any other questions people have asked.
iPad 2, iOS 6.1.3, Contacts use Facebook account - ON