The more I think about social networking products that are intended to expand and strengthen social connections in the name of business opportunity the more I think that they misunderstand the fundamental nature of social capital. Social capital is just that, "capital." If you aren't careful you can spend it all up. Sure, there are some relationships that will be more resistant to fatigue than most -- for example, I am sure that I can make a lot of introductions to my dad before he stops taking my calls. But some relationships are far more tenuous. If you have a good conversation with a potentially helpful business contact at a conference, he will probably take your call or read your email the first time you reconnect with him. But that relationship is pretty fragile and if your initial post-conference contact with him isn't at least mutually beneficial, that relationship will be spent before the second email.