I found this fascinating quote today:
Can you conceive of a situation where you might actually have to ask people for help? Or want to promote something? Anything? Garage sale? Sell your house? Help your spouse or kid find a job? Raise money for a sick friend or relative? You can certainly get on the phone and call people, or send out a group email to all your friends and contacts. But most people, without the benefit of a social network, don't have the network power to make the kind of difference that can be made with a healthy group of online contacts.From Craig Fisher's Blog
You should read the whole article.