goodroi - 11:56 am on Apr 13, 2011 (gmt 0)
I think the guidelines are a good starting point especially for people brand new to SEO. As veteran SEOs we know that the guidelines do not always perfectly match the ranking algorithm. The intent of the guidelines does match the intent of the algorithm.
I would not advocate rigidly following the guidelines. I would suggest you follow their intent of promoting quality content & good user experiences.
Imagine if you give away a free widget repair ebook on your widget site. That you will make your users happy and also gain backlinks from relevant sites. This is a win-win and allowed by the guidelines.