I agree with this article… Google Plus could more easily target Linked In than Facebook… Facebook really has to STUMBLE in some major epic fail sort of way… but I am really not seeing that happen, are you?
The single biggest problem that Google may be up against right now is that they’re fighting a battle from behind. While I anticipate very solid growth early on, once users realize that many of their friends haven’t moved over, rather than have to access yet another social media resource to communicate, they’ll slowly move back to just the one. The one where all their friends and contacts already are, where they can communicate in one location: Facebook.
via 5 Reasons Google+ Is Not A Facebook Killer – Search Engine Watch (#SEW).