A month ago, directories like Alive, Aviva, Bigweblinks were considered in the top of web directories hierarchy. Now they don't even appear for their own domain searches. But they are still in google's index, so they were just penalized and not blacklisted.
I had a feeling this would happen, because on every webmaster web page around the Internet you could see either Alive or Aviva directory listed in the sponsored section. They were too aggressive in getting backlinks.
Many months before the penalization,I noticed they had so many backlinks, they should have been PR8, but they were only PR6. Have been PR7 for a short while then dropped to PR6 although the number in backlinks was highly increasing.
I've seen the owners on this directories on some forums and they seem nice guys, but I am somehow gladly because this penalization happened, it's like the price they had to pay for the abusive way of getting backlinks. But I strongly hope that Google did this automatically and it has nothing to do with human reviews, otherwise it would be totally unfair.
Webmaster forums are filled with opinions about these penalizations and about how alive and aviva and the other directories will regain shortly their rankings. But in my opinion I think they have been banned because of one or more of the following causes:
1) Interlinking schemes (sitewide links between some directories)
2) Duplicate content (submissions titles and descriptions)
3) Mass paid backlinks
And if they fix the problem, they may return but it will take probably some months.
For the rest of directory owners, it's bad because people lose trust in web directories because of these incidents.