Giving you every chance to change your mind about not making a connection, Facebook now gives you two options to deal with friend invitations. You can select either ‘Confirm’ or ‘Not Now’, but ‘Deny’ or ‘Ignore’ are not options.
Selecting ‘Not Now’ moves the invitation to a limbo category that allows those people to still follow your updates in their newsfeed – at least updates tagged ‘Everyone’. Denying a request tagged ‘not now’ involves several steps – account/edit friends/show hidden requests. Clicking on “don’t know (the person)” after Not Now will prevent them from submitting another request.
So this will be a nice feature if you want people to subscribe to you but want to stop short of establishing a two-way relationship. If you have privacy concerns, remember to tag your posts with the level of visibility you want.