Can we no longer vote on Best Answers?

Nope. Part of the last revision when "Green" went to "Purple".

Only the person asking the question can pick a best answer.

Universally disliked.

No when Yahoo! went from the green format to this one, voting for best answer was discontinued. Now, if the asker doesn't choose a best answer the question remains unresolved. Cheating still occurs on this site with or without "in voting."

We can no longer do that. On April 19, 2014 Yahoo made some changes quite probably to cut out the cheating my members with multiple accounts or friends voting for friends answers even when they weren't best answers, now only the asker can choose best answer to their questions.Check the link.

http://yahooanswers.tumblr.com/post/80173794953/im...

They are not interested in our opinions anymore. All they care about is letting us know what they think is important.

Voting was eliminated 3 months back. Only asker chooses BA, if they want to. It will never return

Nope. It was used for cheating. Now instead of being able to use multiple accounts and vote for your own best answer they included a feature which allows level 7 users to move questions from category to category regardless if they asked it or not. If it's working you can count on Yahoo to fix it(read break it).

I've been wondering about this, too. I think it's a very useful feature, and would also better ensure that genuinely good answers get selected as 'best', rather than just something which agrees with the asker.