LinkedIn, the popular social networking site for business, announced a platform that allows outside developers to build applications on LinkedIn as well as for their own sites. The company also added a slew of new features to its home page.

LinkedIn, which has 17 million members worldwide, said that its first partner in the applications program is BusinessWeek, the magazine owned by McGraw-Hill (MHP). At the BusinessWeek Web site, readers will be able to access their LinkedIn connections, look up profiles of people featured in BusinessWeek articles, and search for professional connections at companies mentioned in stories.

LinkedIn is in talks with other publishers and hopes to announce other partners soon, said LinkedIn CEO Dan Nye.

LinkedIn is the latest social networking company to open itself up to outside developers. Facebook has seen its traffic soar since doing so earlier this year. And Google (GOOG) recently unveiled OpenSocial, which lets developers create widgets…or as Google calls them, gadgets…for a variety of social networking sites.

LinkedIn is part of the OpenSocial initative, along with other big social networking sites such as News Corp. (NWS)-owned MySpace and Bebo.

As such, Nye said that LinkedIn’s so-called Intelligent Applications platform will allow programs developed using the OpenSocial model to work within LinkedIn. Nye gave the example of a conference calendar application that shows events people in a person’s LinkedIn network plan to attend. Nye said he believes that many more developers will be interested in creating applications for LinkedIn because of the company’s size and because the platform is truly open, unlike Facebook’s, which only lets people create applications for its network.

“Developers go where the audiences are and they do like open standards,” Nye said.

The new features on LinkedIn’s home page include modules that show questions people in your network are asking, relevant news headlines and job listings.

LinkedIn has added several features in recent months - in September, the company began to allow users to upload photos of themselves for their profile page.

LinkedIn’s rapid growth is said to have attracted the interest of News Corp. , because it could be a good fit for both MySpace and the Wall Street Journal. News Corp.’s acquisition of WSJ publisher Dow Jones (DJ) is set to close later this month. Reports suggested that LinkedIn could be worth as much as $1 billion.

Nye denied in an interview with my Fortune colleague Adam Lashinsky that LinkedIn was looking to be acquired, saying it would take a “helluva lot” to sell out. Nye reaffirmed this in a video interview with me last week and stressed that the company is looking to go it alone.

“All of us in the company are playing to win. There is great potential here to build a great company and we are excited about doing that independently,” Nye told me before our video interview.

I’ve mentioned before that LinkedIn could make sense as a candidate for an initial public offering. Nye told me last week that there were no plans for an IPO at the current time, but he has mentioned in the past that an IPO is something the company is considering.

So will LinkedIn go public? We might have some more clues about that later this week. Classmates Media, a social networking site owned by United Online (UNTD), the parent company of Internet service providers NetZero and Juno, is tentatively scheduled to make its market debut. This would be the first pure-play social networking company to hit the markets in the U.S. (LinkedIn competitor Xing, which is based in Hamburg, Germany, went public in Frankfurt last year.)

If Classmates does well, that could open up the floodgates for companies like LinkedIn and Facebook to also go public. Stay tuned.