I don't believe in the ignore function. The best ignore function is between your ears IMO. If you want to ignore someone, you just do it. At least that's my approach.
Another issue I have with the ignore function is I've read too many posts of people saying they are taking someone "off ignore" to reply to a post but letting the community know they are putting that person back "on ignore" once they are done responding. I believe the late Marketsurfer was guilty of this on many occasions