There is a simple workaround ....
omnifind enables you to configure its "user agent" which enables you to eliminate portions of your content from
omnifind index. Your application should check the "user agent" and eliminate some of the content.
While this workaround seems ingenious I am unable to use it since of the caching system on our CMS.
Any updates for a standard, markup based solution for this (eternal) issue? As a "Yahoo!" engine you might want to look into your own robots-nocontent microformat:
http://www.ysearchblog.com/archives/000444.html