Before I go any further, he participated in the 2007 Boston Marathon, so I admit I'm reaching the well-covered story pretty late. It still remains a nice story.
His name is Jacob. He lost an incredible amount of weight in the training process and used his website -- where he documented his training and life, in general -- as a way of raising money for major charities. (No, it was not a scam. It all went to charity.)
Like I said, that was all pretty well covered. What I noticed on his website, and can't seem to get over, is all the ill-will that was sent his way. There's always going to be weird people out there who will knock down a just cause (Jacob essentially represented three noble organizations) but his site attracted some really strong hatred. Check it out here, where he has compiled a number of such messages. The bright side is that there are a lot of really nice ones in a section he calls "Hall of Fame."