Securing FaceBook account by phone number!

FaceBook is said to be not a safe place to either show your phone number or place your's or others' phone numbers in its posts. Recently, there was also options in WhatsApp (which is now with FaceBook) to opt for using phone number for FaceBook's advertisement purpose. In such a situation, a display in the FaceBook account was shown up that told an account holder to help him to secure his FaceBook account!
Could it be a securing option or anything else after availing this help, it is anybody's guess!

Logging in Gmail by a 'Hijacker'!

Read here how helpful and sensitive is the Google Accounts team! I logged in the Gmail account to find that I am not allowed for accessing it! I doubted my logging in procedure and tried logging in into it again and again twice; but failed to access my account! I thought that somebody might have hijacked my account, and hence became depressed. But here too Google offered a help for me in this. There was a message starting with 'Oops!' and a link offering the help. Through the link I was advised that I might have disabled 'Cookies' and to enable the Cookies in the Settings. I tried next this enabling of Cookies without any hope; but found it work surprisingly that I could access my account with my next logging in! I thanked God for it. What mistake could I have done? I thought about it and after a while I found it: I had cleared the Cookies by using the Clear Browsing Data after my previous logging in into my account! That played such a havoc in accessing my account!
Later on, when I checked my secondary mail inbox, I found an email from the Google Accounts team about logging in to my account by some 'hijacker,' with advice to reset the password immediately!