Has America asked for the extradition of Julian Assange? Sweden is currently asking for his extradition to stand trial on rape charges, I'm not aware that the US has made any attempt to extradite him.
Putin won't give up Snowden regardless of what happens with Amanda Knox.
No one has asked that Amanda Knox be extradited. Everyone seems to be quite satisfied with Knox trapped in her own country. Finally, Sollecito has the same circumstances, trapped in Italy. Knox expressed concern for him after the verdict, most likely because she knew that his Dominican Republic holiday trips had come to an abrupt end. She was prevented from those trips after her release from prison. They had completely different circumstances due to her second conviction. Now, they're in the same situation.
This isn't about Putin, politicians, America, Sweden, Julian Assange, or Snowden, and Russia. This isn't about Britain, Italy, the US or the Ivory Coast. This is about Meredith Kercher who went home one evening, after having dinner and watching a movie with friends. Sometimes between 9PM and midnight, she was murdered. Her body was found under questionable circumstances (to say the least), and three people have been convicted of her murder.
Until Knox is extradited, no one can comment. Petitions to make a legal ruling that Amanda Knox cannot be extradited for murder, or that the treaties between the US and Italy should be disrespected for a convicted murder, seem highly irregular. Does the President of the Unites States want to overlook extradition treaties to excuse one convicted murderer? How do the rest of the people in the United States feel about that? If their child was murdered abroad by a US citizen, would they agree to that person avoiding consequences because of US citizenship?
What about the guy from Alabama that murdered his bride during a scuba diving trip to Australia. Should he be protected from extradition to Australia? He didn't fight extradition. He was convicted and served a couple of years in prison before he was released. He went home and found a new bride. Alabama tried to convict him again, but that was double jeopardy, so the Alabama trial was dismissed.
Extradition treaties seems to be that if someone has been arrested for murder by another country, and that person is a US citizen living in the US, that person can/will be extradited. If someone has been convicted outside of the country, has faced trial in that country and has served a sentence, then that person cannot be tried a second time in the United States (double jeopardy). If someone has been convicted outside of the country and has not served a sentence, and has not served a sentence in the US, then that person should be extradited to serve a sentence (or make arrangements near home) as part of the extradition treaties with Italy.