It's marketing.
Without this type of social media marketing no one would be donating this much to the cause against ALS.
When is the last time you donated to help cure Creutzfeldt-Jakob Disease?
You can say things like, " I see no point in it whatsoever unless the actual act itself donates money somehow." I will give you a couple of points why the act helps.
1.) The act is bringing attention to the donation
2.) By bringing attention to the donation you are giving more motivation to others that wouldn't normally donate
3.) By challenging other you are giving a personal appeal to others to get involved
4.) You ask why do others have to know? Because when you can create a social media fad then you can persuade more to join. Currently, ALSA has raised $88.5 million this year. Last year at this time they had raised $2.6. (financial information comes from Huffington Post)
5.) Obviously, there is a correlation between the ice bucket challenge and the amount of donations that they have
6.) People are having fun for a good cause. You may not find it fun, and that is ok. It's different and unique. People enjoy it.
7.)Are you aware of how the ice bucket challenge started? Peter Frates was a college baseball player diagnosed with ALS. 5 years after his diagnosis (I think it is 5 years it could be 6) he is no longer able to walk, or talk. His wife has stood by him. She also married him after his diagnosis. His friends started this challenge as just a fun way to raise funds for his cause. They challenged a couple of people and in about a month it grew into what it is today.
8.)It's hot outside. People get in cold water for a chance to cool off.
9.)Just another excuse to goof around with friends, family, and co-workers. I did that and we all had a blast. As the poster earlier mention, they did it with their co-workers
So if you want to continue to be negative towards the ice bucket challenge that's fine. Though this is yielding results in fund raising, and helping to find a cure for a terrible disease.
govols I address your question in point 4.