Let’s see what their perspective was, shall we?
On Q&A format:
In Yahoo! Answers, different users can reply with answer to a question, then the asker can select the best answer for that question. In WikiAnswers there is a wiki format which allows users to provide a single answer for each question, and that single answer can be edited and improved by any user.
On contributor personalization:
Users can personalize your profile in WikiAnswers. It gives you more flexibility, such as creating a personal message board, a watch list, a personal community and a personal io page. In Yahoo! Answers, users do not have access to personal networks or other personalizations.
Continue reading the article for statistical comparisons as well. It’s a little strange that they didn’t highlight the fact that while Yahoo! Answers leads the market by a vast majority, WikiAnswers is the fastest growing Q&A site and gaining on their top competitor constantly.