basically it's if Yahoo has a player ranked as one of the top 10 guys at his position he can't be cut from your team. This keeps bad teams from dropping elite players so one of the top teams with a high waiver claim can pick them up. It's a safe guard against cheating basically.
Sometimes injuries or other circumstances may change a players Can't Cut Status but it's rare.
Chevy, I know what purpose it serves. But they do change it during the year and it is not the top ten at his position. There are only 35 guys on the list. I just don't get how they decide to drop some guys but keep others. I am sure there is some logic behind this but I absolutely fail to see it.