So LinkedIn has more than 50 million members in the Asia Pacific region, but how many people do you have in your own LinkedIn network? Why does it matter, anyway? Quantity isn't the same as quality, is it?
With LinkedIn, quantity can matter too. At some point, you might want to reach out beyond your professional contacts to people you don't know. A translator for a language you have not worked with before, for example. A talented web designer. Maybe a freelance writer based in another country; someone you don't know, but whom your peers might, being in the same industry as you are.
The more contacts you have, the more likely it is that someone you know already knows that someone, let's call him Mr X. And if several of your contacts know Mr X, it's likely that they have all worked together before, and he is going to be reliable. You could also ask your contact for an introduction and a testimonial as well.
Then there is LinkedIn's handy 'People also viewed' column, analogous to Amazon's 'people who bought this item also bought' section. The list of LinkedIn members in this column are typically people with the same skills as Mr X. Go through this list, referring to the 'People also viewed' column on each profile, and you can easily amass a whole cluster of people with the skillsets you need.
But if you have a free account, LinkedIn only shows you people who are first or second-degree contacts, with incomplete names for third-degree contacts. First-degree contacts are those you have in your own network; second-degree contacts are people you don't know, but whom your contacts know. Third-degree contacts are literally friends of friends of friends in that they are people your contacts' contacts know. Do the math: the more people you know, the more people you can reach, and the more people you can search for.
Reach a particular critical mass, and everyone you search for will likely be relevant. That's when your LinkedIn network becomes your magic LinkedIn phone book.