When it comes to better indexation and rankings on search engines, when is a good time to do things like disallow search engines in your robots.txt file, use meta robots tags in a page header, or use nofollowing links?  It takes some knowledge and experience to really know what to do in situations like this, and in this episode of Whiteboard Friday, Rand Fishkin helps us all out by covering these tools and their appropriate use in four different situations that SEOs commonly find themselves facing.