I've found it's much more effective to just email someone you're interested in connecting with, introduce yourself, and invite them meet up sometime for a coffee (or beer, depending on the time of day).
If they say yes, it's because they are also interested in what you're doing, and this acts as a quality filter to ensure you're both moderately aligned in your interests and not wasting each other's time. Plus, the one-on-one setting lends itself to more interesting and personal conversations, which tends to have the friend-building effect the original author appeals to.
Networking doesn't come naturally to most people, but being friendly and personable usually does. I find that combining the two removes some of the awkwardness, and makes your efforts that much more effective.