Are you sad for Whitney? Or just pretending to your friends?

The world is full of grief when a celebrity dies, but most of us are stoic about deaths of "ordinary" people far away. How do you decide how to dole out grief?

Tragedies unite people. And on July 23 of last year, the citizens of Facebook and other social media websites were certainly joined in grief.

But they were not mourning the 93 Norwegian victims of a bombing and mass shooting committed by Anders Behring Breivik. Their grief was reserved for Amy Winehouse, who was found dead in her apartment several hours after the Norway attacks.

I posted something along the lines of: "Today of all days, don't waste your grief on her." The comment was, as many made clear, stupid, insensitive and, far worse, preachy.

People are free to grieve for whomever they choose. And that tragedy in Norway did not lessen another person's life. There should not be some sort of fixed exchange rate that values one life over another.

Joe Frazier's recent death prompted heartfelt, restrained messages from boxing fans. The death of Steve Jobs, an individual who had indirectly affected millions of lives, was received somewhat more hysterically. The common thread, however, was fame.

Over the last few days, Whitney Houston's death has again united people. News channels, newspapers and social media websites have been clogged with eulogies, condolences and YouTube clips of the suddenly popular-once-again singer.

Never mind that the latest orgy of grief was carried by many of the same media outlets that for years had savaged her and ex-husband Bobby Brown for their lifestyle, drug addictions and that reality TV show. Celebrities were falling over themselves to wax lyrical about her God-given talents, after years when she had been the butt of cruel jokes.

The Grammy awards ceremony turned into a celebration of her life. And CNN even cancelled a special report on Syria to remember her life.

There were the inevitable "One dies, thousands cry. In Syria ... thousands die, no one cries" online posts. Like the mother that guilts her child into finishing his meal by saying "there are kids starving in Africa you know", these sentiments - like my ill-thought out message in July - missed the point. Life simply does not work like that. There is no reason why Whitney's death shouldn't be grieved - as long as that grief is genuine. More often than not, it isn't.

And it's not only today's celebrity-obsessed media that's to blame. Grieving for dead celebrities is nothing new. People wept when Elvis died, after John Lennon's assassination and when Kurt Cobain took his own life. In 1977, the death of Abdul Halim Hafez, perhaps Egypt's greatest-ever singer, led to suicides by female fans and millions attended his funeral, the second largest ever in the Arab world after Gamal Abdel Nasser's.

But you could argue that in those cases there was genuine grief for artists that shaped generations and affected lives. For all their undoubted gifts, can the same be said of Winehouse or Houston?

But then again, it's not really about Amy or Whitney at all. It's about gestures; it's about tokenism. Just as getting 100,000 people to "like" a page is not going to stop the slaughter of whales in Japan, the general outpouring of sadness, with sincere exceptions of course, has been more about being perceived to be grieving. A pause before everyone returns to posting photos of their latest brunch.

We are desperate for heroes; but are the right people being revered as martyrs?

The former Oasis guitarist Noel Gallagher said this after Princess Diana's death in 1997: "Half the people there probably wouldn't visit their grandmothers' graves, and they go throwing flowers at the coffin of a bird they'd never met." Callous? Perhaps, but you can see his point.

When a massacre is happening in Homs and a catastrophic war on Iran is threatened, our grief is only capable of far more petty gestures.

Whitney Houston's life is no less valuable than that of a child in Syria. But it seems that a child's death, paradoxically, is somehow worth less. Some people just have a higher exchange rate than others.

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