When I blogged earlier this month about some things Matt Cutts from Google had to say about linking, I mentioned something called “cliques” from graph theory. Let me elaborate on this further… I don’t want to bore you all with Graph Theory (although if you’re interested, you could read up on it in Wikipedia), so I’ll cut to the chase. Simply look at the figure on the right taken on Wikipedia’s clique definition page and you’ll see that all 5 nodes (these are the signified as red dots and they can also be referred to as vertices) are all “linking” to all 4 of their neighboring nodes. They never miss a link. It all looks so perfect, doesn’t it! Naturally occurring neighborhoods on the Web aren’t perfect like that. If it looks perfect, it’s been engineered. Google will be suspect to unnatural-looking neighborhoods. So if you own a stable of web sites, think twice about linking every one of these websites to each other in a completely symmetrical fashion.