One more non-perfect example supporting the idea is related to the "Seven Habits of Highly Effective People" by Stephen R. Covey. My father had adviced me to read the book when I was about 15 years old. I did read it, but several years later - when I was 19. The thing that made me open the "Seven Habits" was a blog entry mentioning it by an individual whom I admired but never knew personally. I say that the example is not perfect because it fits precisely to the title idea of the entry - the book was recommended by two distinct persons and that may have made me start reading it. At the same time, the question of how I prioritize recommendations depending on their sources has first occupied me exactly in context of the advice that led me to reading the "Seven Habits" book.
Sincerely speaking, I can't find any good reason justifying such a strange priorities. The only idea I have about these is that most blogs and papers from which I get information on books are somehow connected to the fields of my interest whereas my father has nothing to do with, say, Computer Science or programming. This may be the point why I pay more attention to the recommendations from the blogs than those from my relatives - the former are just closer related to the stuff I am interested in. Still, this belief of me paying less attenton to my relatives' tips may prove to be false - especially considering the fact that I have read several books on economics that my father encouraged me to read - but, in case I'm not mistaken about the existence of such a rule, there must be some better explanation for such a strange prioritizing - an argument I can't formulate right now.