Join the discussion at http://tinyurl.com/65nm74
I borrowed this question from a LinkedIn group discussion board (http://snipurl.com/53kna).  Here is my posted answer:
I like the question as a way to start a good discussion.  Here are several actions that people can take to expand their professionals networks:
 - First, you have to be in the presence of someone – [...]

Are you a LION? Are you uncertain if you
should be concentrating on getting
connections of quantity or quality for your
best business results?
I just received ANOTHER invitation that used
a canned text. And I can almost recite it verbatim.
It was the third or fourth time this person with
500+ connections has invited me to join his
LinkedIn network.
I joined LinkedIn [...]

I admit that I am a big fan of online networking sites, using LinkedIn, Meetup, MySpace, Urbanmelt, Facebook, Yahoo groups, Ning, Google Groups and other sites for social and business networking.
I also have found that some are very easy to use and others are very difficult.  This will obviously differ with the skills of each [...]

Q: Hi Jason,
I just got an email from a vendor who supplies a different service to the same type of clients as I do.  He didn’t blind carbon copy it, so I now have access to about 200 email addresses of folks who, in all likelihood, would be interested in what I have to offer.  [...]