Amitabh, who turned 70 on October 11, guards his privacy fiercely and says his blog is "just an interaction with people who are followers".
"I don't write it (blog) because I want to document my life. I have never done that. All that I put on my blog is not necessarily all that I wish to share," Amitabh said.
"There are certain things that I don't to share. There are certain remarks, opinions, which I think are personal and should remain so; I don't comment on that. It's just an interaction with people who are followers and who affectionately want to converse with me. It's not done with an idea to document my life," he added.
Amitabh has been living the celeb life for four decades. He rose to dazzling stardom in the 1970s with hits like Zanjeer, Sholay and Deewar, then saw his health and career decline after an accident during the shooting of Coolie in 1982. In the 1990s, he tried to resurrect it with damp squibs like Lal Badshah and Sooryavansham.
His tryst with the small screen as the host of Kaun Banega Crorepati helped him embark on another glorious journey, making him one of Bollywood's most enduring stars.
Despite all this and much more, the man himself feels "there is nothing to document".
"Secondly, if there is any documentation that needs to be done, it needs to be done in a much more professional organisation... than to do it myself. I don't know how to write an autobiography.
"I will never be able to write one and I will never write one because I personally don't feel there is anything worth writing," said Amitabh, who never misses his date with his blog.
His father Harivansh Rai Bachchan penned his autobiography, why can't he?
"I am happy that my father wrote his autobiography and therefore I am able to gain whatever I could from his works, what happened prior to my existence and for a certain portion of my life when I did exist. But, other than that, the media has got more material than I have. Even though it may not have justifiable information, through this medium (blog) I am able to correct if there is any mistake or if there is a wrong representation," he said.
Amitabh admits he often gets suggestions to write an autobiography, but doesn't see any value in it.
"I don't think in advance what I want to write on the blog. After working the entire day, when I sit in front of the computer and put the date and day after that whatever I think and I feel I start writing. And at times all of a sudden because of some technical problem it just disappears and it feels so bad...that moment just slips off."
However, he has learned his lesson and become cautious. "I save it... Now I am taking some precaution."