It’s simple, as most things which work are.
The answer to the secret of online networking is time.
The reason it’s a secret is not that it can’t be seen, it’s because people chose not to see it.
Anyone can build an online network to help them with diggs and stumbles and reddits and even links, and getting someone to write about you. But you have to pay the price in time, either spend your own time or pay for another persons time.
An hour a day for three months will build you a very nice network. Of course you have to do all the other stuff, but that’s for another blog post.
You can only build your network quickly if you bring something else to the table, like a TV show or a sex scandal.