Whole-heartedly agree. Tons of people are successful because they are "master networkers". "I'm looking for a XYZ" "Oh good, talk to So-and-so, she knows everyone!" Networking in the business world is very powerful and putting people "in touch" with others is a highly valuable transaction (mostly without direct compensation).
Unfortunately, this is not a problem for a master networker and this is much more valuable to an employer. If I am a master networker, than I continually improve on my ability by doing just that - networking. Having a tool to help me may give me a competitive advantage may indeed help. However, this will ultimately lose out when network effects set in. It will easily be gamed by people.
Just recently I got an e-mail from a friend asking if I know anyone to fill two highly regarded director-level positions. I referred a friend, but I don't think I would ever use a service to do such a transaction. It would relinquish much of the value of the transaction - that its a person I trust referring someone.