I agree with previous comments that the paper did provide a unified view of segmentation based on eigenvectors of one form or the other of the affinity matrix. I think the gain a deeper understanding about why and how these algorithms actually work one must read some of the papers suggested by Greg and Sameer. Without sufficient background knowledge i found the explanations presented in the paper weak. Then again, the point of the paper was not to explain why the algorithms work but rather to provide a unified view.

I also found that the paper was lacking the experimental results. Examining such results for all of the presented methods could give more insight into how these algorithms are different.