Hi Jim,
If you are using the "old" Yahoo version, it allows you to mark the message in the bulk folder and click the "Not Spam" button. This worked for me after one or two tries with other forum messages that were showing up there.
Not sure if that capability exists in the "new" version. I had it for a while, but switched back due to the annoying ads that blocked out the right side of the screen after every refresh.
Hope this helps,
Fred