Robots tag on Wordpress blogs ?

I just know today that there’s some blogs that’s using these meta tags at their pages

meta name='robots' content='noindex,nofollow'

For those who didnt know that those meta tags are mostly used to block spammers from putting their links on a high page rank sites just to get a higher page rank for their sites. But by using the nofollow tags, you've already block the spammers from getting a higher rank for their pages. But a noindex tags ? well its just to harsh for me, since a noindex tags means that the search engine bots shouldn't index (crawl) any links found on your page. But i think there's a reason for that but i just don't know why ... and that's all about it