I'm usually happy to see Stack Overflow in my search results, but I was reminded of a flaw this morning when I searched for "Manhattan layout algorithm". I clicked the "Show more results from stackoverflow.com" option. It turned out that a number of the SO listings appeared only because they all had the same link in the "Related" sidebar. I don't know if this is a common problem with other sites that list internal links in sidebars, but I only seem to notice it in Stack Overflow results.

(Unfortunately, I never did find a good description of the algorithm.)