The need for recommendations could be a possible source for the development of added services by social networking companies like Friendster. I've written about that before. But they (your friends) are not necessarily the best source for recommendations on everything, it's important to remember that.
"In other words, the assumption that there's a correlation between the people I like and the products I like is a flawed one. To use an analogy, Bill Joy, the co-founder of Sun Microsystems, famously uttered this truism (now known as Joy's Law): "No matter who you are, most of the smartest people work for someone else." The same might be said of recommendations. No matter who you are, someone you don't know has found the coolest stuff."