In Bound Links Type

I met up with a friend over the weekend and somehow we started talking about Search Engines.
He said something which I found strange and I thought I'd ask in the forum, that the important thing is to have inbound links it does not matter if 1, if it is relevant to my site or not or
2, if all of it are from the same site.
I believe he knows what he was saying but I was too dumb founded to ask him to explain. Is there any drop of truth in this and can anyone help me turn the light on on this?
Regards,