If Facebook acts like an online dorm room, with millions of people on the social network “poking” each other, dedicating songs and displaying favorite videos, MySpace is more of nightclub, says Max Levchin, founder of application factory Slide. “You can’t get too crazy on Facebook,” Levchin explained Tuesday night as he dodged cheeseburger-munching software developers packed into MySpace’s newly-leased San Francisco loft. “We’ll see what we can do on MySpace.”

Levchin, along with the founders of the other leading online widget shop RockYou and 200 or so other developers were here to get more details — and free booze and food —  from the company’s co-founder and CEO Chris DeWolfe and the MySpace technical team about the social network’s newly-launched open platform.

MySpace’s key rival in the social networking world, Facebook, has had incredible success in the eight months since it invited developers to get under the online services’ technical hood to write applications that not only draw members in but make money. As of yesterday, MySpace, using the specifications of Google’s Open Social initiative, is officially getting in on the action.

DeWolfe, cruising through the crowd of mostly twenty-and-thirtysomething guys, in a hipster hoodie and jeans, looked pained by the suggestion that MySpace is following Facebook’s lead. “We’re the original open platform,” he says. “We’ve always been open to all demographics, we let our users customize their pages we didn’t restrict them, and we have been open to other developers’ sites like YouTube from the beginning. This is the natural next step for us.”

That step includes a set of APIs, available now, that developers around the world can use to build applications for MySpace. Security will be of paramount concern, MySpace CTO Aber Whitcomb told the crowd of developers. “Make sure you don’t annoy the users,” he admonished the crowd.

Some of the details are still uncertain, chief among them, how applications are picked for distribution on MySpace, and what developers can do to market their software creations to as many MySpace members as possible – to get viral, in the hacker parlance.

Whether MySpace is successful in its open platform initiative will depend on two very simple things: how easy it is for developers to get their applications up and running on MySpace, and how much money they can make. The first part seems answered already.

Guys like Levchin and Jia Shen, co-founder and CTO of RockYou were showing off applications running on MySpace Tuesday they had cobbled together the night before. “I did this between 11 and 3 a.m. last night,” Shen said, looking awfully awake considering. “And it works fine.” The application he had running was a version of a Facebook application called “Emote” that lets people add a huge number of souped-up emoticons to profile pages.

Shen says he is impressed by the ease of writing applications for MySpace, but also by the attitude shift he sees in the News Corp.-owned unit . “In a matter of weeks MySpace seems to have gotten rid of their big company mentality and are back to what they were at the beginning,” Shen says. “Their technology is much better, and they have done a complete reversal on outreach to the developer community – a year ago, you never knew how they would react, whether they would block your application or not.”

Levchin says he is looking forward to the different kinds of applications you are apt to see on MySpace. “The more obscure and bizarre to some extent the better, because the reach of MySpace is so huge, you will find an audience,” he says. “If you are some expert on some sub-culture, you should be building an app for MySpace. I am sure we will be surprised by what succeeds. There are going to be some really cool, random applications that just take off.”