Yesterday, TechCrunch covered the $1m that eBay / PayPal had raised for Japan earthquake and tsunami relief. It's been heartwarming to see such big brands and platforms leverage their communities - and their scale - to promote giving. From PayPal (who is in a position to promote spending) to LivingSocial (who is matching donations) to Causes (who has the perfect community & brand) to Starbucks (who promotes giving as soon as access the web via their network)
It's terrific. A few screenshots below. This is not meant to overlook promotions by others - feel free to mention them in comments below.