Editor’s note:   Some savvy Facebook engineers rigged the NASDAQ button to automatically post “Mark Zuckerberg has listed a company on NASDAQ – FB” to the CEO’s Timeline as he  rung the bell to open the NASDAQ’s day of trading. David Garcia, a senior software engineer at Facebook, explains how they turned the NASDAQ on to Open Graph.

Facebook is now officially a public company as its shares began trading on the Nasdaq this morning priced at $38 a share , giving the social network a potential market cap of $104 billion for the largest Internet IPO in history. CEO Mark Zuckerberg rang the opening bell from Facebook headquarters in Menlo Park, Calif. Employees spent all night on the company’s 57-acre campus for a hackathon event where they worked on new projects of their choosing

As if anyone needed any more proof that the Samsung’s Galaxy S III would sell like (slightly more expensive) hotcakes, a report from the Korea Economic Daily reveals that the long-awaited handset racked up over 9 million pre-orders from mobile carriers across the globe.

Facebook began public trading today at $38 a share and a valuation of $104 billion. These are the top 25 apps on the social network the day of its initial public offering, as tracked by our AppData traffic monitoring service. We’ll start with daily active users, which is a measure of the most engaged portion of an app’s audience

The Facebook IPO is expected to usher in a day of massive trading volumes on the markets, and some believe that might translate to a lift for some tech stocks . But one that could really use some help has just been served another course of bad press: Nokia is apparently burning through its cash reserves — fast.

Facebook’s $38 share price would make its deal to buy Instagram worth nearly $1.2 billion, up from the roughly $1 billion price the company announced in April .

Pulse , the popular free mobile news reader for iPhone, iPad and Android, could soon get ads. Until now, Pulse, which launched its first app in May 2010, was ad free and the company focused more on user acquisition than monetizing its service. A new job posting on Pulse’s site , however, clearly spells out the company’s plans to start making money through advertising in the near future.

It’s been about a month and a half since peer-to-peer bike rental service Spinlister launched in San Francisco and New York .

Facebook posted new jobs for head of policy in Japan and Korea this week. There was also a data center position, marketing and recruiting jobs posted on Facebook’s Careers  page

Facebook hired engineers and marketers this week, according to its  LinkedIn  feed and Careers  page. The company also appeared to hire a manager of State and Local Public Policy – California and legal counsel in its India office. As we covered Tuesday, the company also hired the team behind Android photo sharing app Lightbox