The San Francisco-based startup has become the go-to website for share-happy professionals. Now it’s hoping to lure its users to spend more time (and money) on its site by launching a web conferencing tool that will compete with deep-pocketed players like Cisco Systems’ WebEx and GoToMeeting from Citrix Systems.

If you’re not familiar with SlideShare, it’s basically a public database of corporate presentations, university tutorials and even graphics from President Obama’s recent State of the Union Address (posted by the White House). One of the most popular uploads on the site is a corporate culture primer by Netflix (NFLX) CEO Reed Hastings, which has garnered nearly 700,000 views.

SlideShare may have helped make corporate presentations cool. But it’s a newcomer to the more competitive and lucrative web conferencing world, which is currently dominated by much larger companies. Still, the startup believes its new service, called Zipcast, will be more viral and social than existing products from Cisco (CSCO) and Citrix (CTXS), and promises “deep integration with social networks.”

Unlike some other services, SlideShare’s doesn’t require any downloads and is entirely browser-based. To get started on Zipcast, users can sign up through SlideShare or their Facebook Connect log-in. They can also invite colleagues to join a meeting via Twitter and share chats (in real-time) on their social networks. In case you’re looking for even more random people to listen in to your company’s budget meetings, SlideShare’s homepage will display an activity feed of all public Zipcasts as they’re taking place.

Of course, not every company will want their online conversations made public. In fact, I’m betting most of them won’t. Those who need private, password-protected web meetings will have to pay for a SlideShare Pro account, which starts at $19 per month (WebEx and GoToMeeting cost about $50 a month).

SlideShare is hoping its pricing model, integration with social networking features and existing community of share-happy professionals will give it an edge over the competition. But it’s not the only company trying to make standard business tools as social and user-friendly as consumer experiences.

There’s been lots of activity in the social business software space in recent months. In January Salesforce.com (CRM) paid $31 million for video-conferencing service DimDim. And companies large and small have been trying to bring Facebook-like social networking features to the business world for years.

SlideShare has similar ambitions, and says it will build tools that allow professionals to share content in whatever way they want. Right now, its existing customer base of PowerPoint addicts is probably its strongest weapon against the competition. Starting today all presentations will have a Zipcast button that will let users launch a meeting from any of the thousands of slides they or anyone else has uploaded to the site.

But while Netflix’s Hastings might be happy to share his corporate culture manifesto with the world, it’s unlikely he wants his company’s strategy meetings to go viral. Then again, while most corporations would likely opt for paid, password-protected online meetings, a younger generation of professionals might be comfortable using the free, public version of Zipcast. That’s good news for those of you out there who are just itching to sit through some stranger’s latest PowerPoint presentation — now you’ve also got a random company’s titillating HR compliance meeting to view.