LinkedIn, a social networking juggernaut by anyone’s standards and one of the few successful social sites targeted at business users, announced today that the company had secured an additional $22.7 million in Series D funding. The investment brings its grand total for Series D to $75.7 million.

During these uncertain times for many Web companies, the investment marks a decided vote of confidence in LinkedIn’s strategy. Perhaps more importantly, the admittedly “strategic” investment hints at some potential partnerships for LinkedIn in the coming months.

The follow-on funding included investments from Goldman Sachs, The McGraw-Hill Companies, SAP Ventures, and Bessemer Venture Partners.

LinkedIn CEO, Dan Nye, highlights:

“This funding strengthens LinkedIn further, and will help us to continue creating additional services for professionals to connect and collaborate more effectively, around the world.”

What sorts of “additional services” might those be? It wasn’t long ago that LinkedIn announced a content partnership with The New York Times. It doesn’t take a drastic leap of faith to imagine a similar partnership with McGraw-Hill’s BusinessWeek.

SAP brings another potential partnership to the table. ReadWriteWeb’s Bernard Lunn has hypothesized that “LinkedIn could replace Outlook and SalesForce.” With SAP and its suite of business tools in the mix, that hypothesis could quickly become a reality.

But those are simply educated guesses. What’s certain? LinkedIn is profitable, it has money in the bank, and it just convinced some additional heavyweights to invest in its vision. And that accomplishment – especially in light of the current financial atmosphere – is not to be taken lightly.