IT'S funny how that which in life would seem madness, online is perfectly fine.

If you needed attention, say, ­hailing a bus or calling for help after being hit by said bus, pouring a bucket of iced water over your head might not be the wisest way to go about it. It would probably get you attention, but it might not be of the type you were trying to attract.

Online, however, pouring ice over your head is the new no make-up selfie. That is, #nomakeupselfie.

Remember those? They started innocuously enough on March 5 when the novelist Laura Lippman tweeted a bare-faced photograph of herself to show solidarity with the actress Kim Novak, pictured.

Suddenly, Lippman was inundated with pictures of lipstickless ladies and somehow this became a force for greatness, raising well more than £8 million for Cancer Research UK.

Understandably, charity marketing execs everywhere are trying to replicate its success.

Cancer Research UK is already back on it, with its fight face campaign #wewillfight. The premise of this one is that you take a photo of your "fight face" and post it online. Again, it's awareness-raising, despite increasing criticism of using fighting language to talk about cancer.

And now we have the Ice Bucket Challenge. While the success of the #nomakeupselfie came from its organic growth, the Ice Bucket ­Challenge is less natural.

Begun in America to raise awareness of/money for ALS, the challenge is that you pour a bucket of iced water over your head when nominated online by a friend. Refuse to do it and you have to donate to an ALS charity. So far, millions has been raised. I have to admit, I had never heard of ALS before (Amyotrophic Lateral Sclerosis, also known as Lou Gehrig's Disease) and I imagine there were plenty of others in my shoes.

In a way it makes donating seem like a consolation prize by not having the forfeit come after the refusal. The campaign could do with a wee tweak. How about dumping ice on people who refuse to donate? Or have people ice themselves and donate?

These viral trends will only become increasingly common as charities attempt to harness the power of the internet and global reach of hashtag activism (hash­tivism?). It's a rich seam to mine but there perhaps should be clearer links between the dare and the cause. Otherwise, people will reject the trend and the charity it represents.

After all, one of the main ­symptoms of a virus is fatigue.