First Off Jason was the second Robin right after Dick Grayson, among many fans at the time he was not very well liked, so in order to fix that DC decided to have a vote that would determine weather Jason lived or died and majority voted death and he was killed off. Now looking back on this, I still say it was a very poor decision to have the fan-base vote if a character lives or dies and I believe the company would agree seeing how they have not pulled a stunt like that every since.
Prior to the release of Batman #617 (cover dated September 2003), a page of art from the issue by artist Jim Lee circulated the Internet, apparently revealing the mystery villain Hush, who was the focus of Lee and writer Jeph Loeb's "Hush" storyline, as a resurrected Jason Todd. The following month's Batman #618 (October 2003) revealed that the appearance of Todd was in fact a ruse by the villain Clayface under the direction of the Riddler and Hush. Loeb explained, "I always liked Jason, liked the idea that Batman had a Robin who died in the line of duty and how that would motivate anyone to continue their quest. It would also be the most recent, most painful thing he had to endure. That's why Hush played the card—to get inside Batman's head... But 'Hush' wasn't about Jason—Jason was a pawn to be moved around the table... If someone else wanted to tell another Jason story or bring him back and we at least opened the door, that's great!
In 2005 writer Judd Winick began the Under the Hood storyline that revolved around the mystery of the identity of the new Red Hood. The character's identity was revealed as Todd in Batman #638. Winick explained that after his initial arc on the Batman title, he suggested doing "something big" to his editors. Specifically, he wanted to bring Jason Todd back from the dead. Winick said, "I was less interested in the how and the why and the what of Jason Todd returning from the dead than I am about what Jason’s return will do to Batman. Now."
Jason has had many persona's such as a murderous version of Nightwing, Red Robin and even a killer version of Batman and Grant Morrison has his take on the character in his Batman and Robin run in 2010.
Now the thing I've really like about Jason since he's been back is in many ways he represents the audience point of view in the Batman Universe. He is the one who ask questions like "why won't Batman kill the Joker?" "Why put criminals in Arkham Asylum when they should be put on death row?" These are the same questions that Judd Winick put in the animated movie Batman Under The Red Hood(which is a much more improved version of the under the hood story line he wrote when he brought Jason back, he wrote the story so that it made more since.)
Batman Under The Red Hood was very well received, so much so that Judd returned to the character again and gave us Red Hood Lost Days, a six issue mini series which goes into more detail about how Jason came back from the dead and his lead up to becoming Red Hood. The popularity of this character has really grown over the past few years, some say he's become the DC Punisher, some say he should have stayed dead but I am not one of them.
Recently Winick has written a 3 issue Batman and Robin story arc involving Jason again and him becoming Red Hood once more. Jason may be Batman's greatest failure, but in modern times Jason has become a very ingenious character, he's the one member of the Batman family who is willing to take it to the bad guys as hard as they bring it to the good guys. He's morally ambiguous and I like that their is a character like this in the Batman universe and in DC comics period. That is the character of Jason Todd and why I like him. If you want to know more about Jason check out his wiki page here. http://en.wikipedia.org/wiki/Jason_Todd
