What do Facebook, Shell and Pfizer have in common?

They all use software by Atlassian for product development. The Atlassian name may not have the same familiar ring to it as heavyweight software players like Oracle or Salesforce.com, but the company just got a major endorsement from Silicon Valley venture capital firm Accel Partners.

AtlassianDudeAccel invested $60 million in Atlassian on Thursday, representing the firms’ largest single-round bet on a company in nearly a decade.

The cash infusion should allow the 8-year old Australian company to ramp up its international expansion, make some acquisitions and provide liquidity to employees,  said Accel partner Ryan Sweeney, who led the investment along with Accel partner Richard Wong.

Atlassian, whose products allow companies to collaborate on product development and do things like track bugs, generated $59 million in its fiscal 2010 and has been profitable from the get-go, , according to Accel.

Accel isn’t saying how much equity it got for its $60 million other than to note that the VC firm now has a minority stake in the company and a board seat.