it will stop your blog been even crawled if your settings are wrong. goto.... wp-admin > settings > Privacy put a tick next to "I would like my blog to be visible to everyone, including search engines"
Sorry, I don't think I worded my thread very well. Previously Wordpress blog catogories had a do-follow on there pages therefore you got a backlink from a high PR page e.g. food tag page Now they have no-followed the links i.e. not more good backlink = no more chance of gaining high PR blogs quickly????