I have a couple of email addresses. I doubt I am alone in this fact. I have one at work, one that is associated with my internet provider that I use for personal business (stuff I buy on-line, banking, ect.), one that I use for personal social stuff (facebook, friends) and one that I have used when doing 419eater.org stuff.
There is a bit of mixing and some very old friends use the address I use for personal business stuff, but I do not share the address with strangers. None of the people are share-aholics. However, one of my friends occasionally "shares" and I believe a recent linkedin invitations (yes, more than one) were from one (yes, one guy) of the other people on that particular email. I've never met the guy and we do not work in even remotely similar industries so I have zero reason to network with him.
It is just creepy to throw any old email you get your hands on into your linkedin invite list. You might think linkedin is the best thing since sliced bread. I don't. And if you didn't put that address in yourself, then linkedin has some pretty good spyware on your computer that you let linkedin put on your computer and that is creepy, too.
So all you linkedin stalkers - Go away and take linkedin with you. Don't bother me on a personal email address. I get annoyed by enough linkedin invitations from legitimate people who actually know me where linkedin invites should be: on my work email address.