I just noticed this and wasn't really sure the reason, but why would Yahoo use nofollow in its on SERPS for enhanced results. To me it seems to make no sense since they don't give any attribute to that link anyway, so why do it on their own site?
For example: Search for widgets in yahoo. The "enhanced results under the main title all use the nofollow command.
hmmm... I'm not sure about that but Can I be linked it with yahoo spider's processing web pages? less pages.. better for yahoo? My small - medium size web sites are Ok in Yahoo, big web sites... many problems in yahoo