British-born American firebrand columnist, author and activist Christopher Hitchens is dead. But his admirers are keeping his memory alive by mourning his loss on sites like Facebook and Twitter.

Hitchens, 62, died after a prolonged battle with esophageal cancer.

Celebrated novelist Salman Rushdie tweeted: Goodbye, my beloved friend. A great voice falls silent. A great heart stops.

Columnist Tony Parsons' tweet says: Christopher Hitchens was a one-off, a trouble maker, one of the greatest writers alive and also a smoker. He deserved 30 more years of life. 

Illusionist Derren Brown tweeted: Damn, just heard we lost the Hitch. We're one giant down.

Comedy writer Danny Baker wrote: The news of Christopher Hitchens' death is somehow still a jolt. A fierce and raging light goes out.

Hitchens' numerous fans have also taken to the Internet to express their condolences:

Tom Jamieson: RIP Christopher Hitchens. Would be nice to think God does exist, simply for the earful he's getting right now.

Tommy Hough: A middle of the night RIP to Christopher Hitchens. I didn't always agree with him, but he walked it like he talked it. 

Nicola Balkind: RIP Christopher Hitchens. May none of your obituaries contain the phrase 'after losing his battle with cancer.'

Manko: RIP Christopher Hitchens, thanks for your inspiration, intelligence, strength, and all the hitchslaps I shall never stop using. Sad day...

 Mike Bostock: 'People who put their trust in money and capital are fools. It's going to disappear like fairy gold' - Christopher Hitchens.  

Peter Bradshaw: I knew Christopher Hitchens a bit in the 90s. As a writer, he was a Jimi Hendrix in an industry full of session rhythm guitarists.

Michael Shermer: Christopher Hitchens died. We shall miss you, your voice, your pen, & most of all your mind Christopher. The world (was) better because of you.

Vanity Fair: Christopher was the beau ideal of the public intellectual. You felt as though he was writing to you & to you alone.

There are many more tweets, not all of which are RIP messages. Instead, they talk about him and everything related to him - his work, his videos, his photographs and his quotes.

Christopher Hitchens is very much alive, if only in this world of tweets.