Israel Frees 255 Prisoners

Article discussing the release of 255 prisoners into the hands of Fatah. I don't really understand - what did Israel get in exchange? The prisoners released signed a piece of paper saying they won't hurt Israelis - wow, now I'm sure everyone feels secure. And I love this quote - "Palestinian Prime Minister Salam Fayyad said Israel needs to do more to improve the atmosphere." Hmmm right, because Israel is getting so much in return, yeah, I see. I don't get it.