I just found this article which came out today, looks like advertisers are running a littel scared...proves that beta won't be finished till end of this year or early next maybe. http://www.ft.com/cms/s/3d163758-47fd-11db-a42e-0000779e2340.html
read the article...Yahoo is not making enough revenue, which is scaring off the advertisers...therefore if less advertisers, then less ads for the publishers...they can't go public if they can get advertisers