I’ve seen two dofollow links in yahoo answers here (the 1st one) and [URL=“http://answers.yahoo.com/question/index;_ylt=Ah8OcDB0Qejv4Tv3t4Etqi4jzKIX;_ylv=3?qid=20120629121100AApFJu2”]here (also the 1st one), while the other links on the same pages from other answerers are nofollow.
I don’t see any dofollow links on those pages other than the ads. :-/
Here, the link to sweathelp.org is dofollow (I’ve checked the code and there’s no rel=“nofollow” attribute). Also my seo site tools plugin shows it’s a dofollow, and it shows one nofollow link in one lower answer on the same page.
OK, I’ve found it. I had a plugin in chrome “fastestchrome” and I had “linkify text urls” checked.
You should not focus on terms like “dofollow” and “nofollow”. If you are focusing on these terms, then odds are your link building strategy is outdated.
Yahoo Answers links are very high value in terms of boosting your ranking in Yahoo, but Google will not rank a site high unless the backlink profile is diverse and natural.
No, it’s not a link at all. It’s just a URL within the text. It’s only a link if it has anchor tags around it.
EDIT:
OK, I’ve found it. I had a plugin in chrome “fastestchrome” and I had “linkify text urls” checked.
O, I see. 
In don’t see your dofollow links at that yahoo answer site. All of the links are dofollow at that page that you suggested to show us.
yahoo don’t allow dofollow links as per what I know
All mentioned URLs have nofollow links and there are not any dofollow link. You can see rel=“nofollow” in the source of all links. so they are nofollow links.