According to SER, the PageRank metric has been removed from Google Webmaster Tools, after the search engine realized it was talking out of both sides of its mouth, all the while it continued to display the infamous metric:
We’ve been telling people for a long time that they shouldn’t focus on PageRank so much; many site owners seem to think it’s the most important metric for them to track, which is simply not true. We removed it because we felt it was silly to tell people not to think about it, but then to show them the data, implying that they should look at it.
The problem is, Google’s not yet ready to remove the PageRank score from the toolbar installed on hundreds of millions of web browsers. This really leads you to conclude that role of PageRank has been reduced to nothing more than a comfort blanket for SEO noobs. I say this, with a high degree of confidence that most experienced SEOs pour over the data in Google Webmaster Tools, whereas those new to the industry likely let the toolbar be their only guiding light.
Having said all of that, I will admit that I still find the PageRank data useful. No I don’t use the Google Toolbar–I prefer the Firefox plugin called SearchStatus–but I do sometimes glance at the PageRank of a page. But, before you start pointing and laughing at me, know that I only use it as an early warning that a site is not behaving in Google’s index. Any green means “go.” No green, means there’s something to investigate.