When you receive a request to connect in Notifications you can CONNECT, KEEP or BLOCK. When you CONNECT to someone, they get your contact info and anytime they change their info it automatically updates your phone's address book. When you KEEP a connection request, the requestor's contact info is added to your Contacts but you ARE NOT connected so they will not get your contact info in return.  If you BLOCK a connection request, their contact info will NOT be added to your Contacts and they will not be able to send you a connection request again.