I'm not against this idea, but I'm not sure that someone acting as third party to collect donations and later send it to charity is really needed. These people who want to donate is already doing it themselves without intervention of third parties.
I remember theymos in past said that Bitcointalk don't really need revenue from sold ad slots, because they have lot of BTC in reserve. So, maybe Bitcointalk can donate part of their revenue to charity, together with this pool?
And if such charity pool will be made, we should be sure that 100% legit charity organisation will be chosen. Because in past I read some bad things about such big organisations like UNICEF, that not all donations reach people who really need for it. So, sometimes I prefer to donate to local animal shelter instead of big charity organisation to be sure that my donated money will be spent in a right way.
No theymos don't involves badges, I see a situation where forum users will only donate just to be recognized via badges which goes against the whole idea of charity. I'll love it, if every one could donate anonymously e.g I won't what to be judge based on the amount of bitcoin I can afford to donate.
Even if some people donate just to be recognized, it's nothing wrong, because they're still helping with their money. Your post reminded me some celebrities or millionaires - I'm sure that some of them donate to be recognized or to it's just PR. But still, they are spreading avareness about charity, advertise it and it helps to attract more donators.
BTW, on Bitcointalk we have "Donator" badge for people who donated 50 BTC and more. I doubt that they donated money to get badge and be recognized here...