So far, no outside/foreign social networking site have successfully exploit SE Asia even after their explosive growth in that region.
Friendster, dead.
Multiply, dead.
Plurk, soon to be dead (or dead already).
There's a big boom in Asia in general that is a known fact. But when it comes to SE Asia, the profit margin is small in USD unless you're operating under the local currency (i.e.: have your office there, do your business there, etc).
If the HQ is in SF where everybody lives and breathes SF bubble and not in SE Asia or Indonesia, you won't have much insight other than some generic dataset (country X loves to post pictures, for example).
Web-apps that make money tend to be E-commerce sites (http://tiket.com) that have complex affiliates behind it.
Eyeballs type of apps (web, mobile, anything) generate lifestyle business, not Facebook level IPO.
The real winner is the founder who can flip his/her company for multi-million-(usa)-dollars to the highest bidder (typically the conglomerate family).
PS: Oddly enough, SE Asia is where the phone companies peaked and die. Nokia, Blackberry, the pattern is striking!