Article by Pierre Zarokian
In a video published April 24, Matt Cutts addresses the question: Does linking two sites together violate Google’s guidelines?
The answer to this question is no. According to Cutts, linking two sites together that are related does not violate Google’s quality guidelines. However, Cutts goes on to vaguely explain how many links are too many.
According to Cutts, you could violate Google’s quality guidelines if you begin to link 50, 80, or 150 sites together. In Google’s eyes, linking such a large number of sites starts to look like a linking network, and something that is artificial as opposed to organic. Still, it’s hard to say how many sites are too many. While Cutts doesn’t give an exact number, he does say you link no more than a small number of sites together, a number you can count on one hand.