Nitro, the other PDF software company, raises $3.5 million

When you think about PDFs — those maddening, borderline-useless, wish-they-were-obsolete files only a print designer could love — you probably think about Adobe. But at least one startup wants you to think of Nitro instead.

Nitro is an Australian-founded, San Francisco-based startup that’s all about editing, reading, signing, and convering PDFs, and the company has just raised $3.5 million.

The new infusion of cash should help the company continue its product development and marketing; however, reps for the startup tell us it’s already doing pretty well in terms of adoption. The company’s free product, Nitro Reader, has had 75 million downloads and gets around 3 million unique users each month.

However, around 150,000 paying customers have upgraded to Nitro Pro, the startup’s PDF creation and editing suite. The Nitro spokesperson tells VentureBeat that today’s funding will help the company double in size by the end of 2012.

Here’s a brief demo video showing how Nitro Pro works:

[youtube http://www.youtube.com/watch?v=C8KS5Sc-8D4&w=640&h=360]

So, where’s Nitro heading next? If you enthusiastically hollered, “Into the cloud!” you’d be right. Part of this new round of funding is intended to take Nitro from a downloadable software suite to a cloud-based business collaboration workflow for the enterprise. Buzzword-eriffic!

Nitro was founded in 2005. This is the startup’s first institutional round of funding; until now, the 50-employees-strong company was bootstrapped.

Today’s funding comes from Starfish Ventures, a venture capital firm with roots in Australia. Starfish’s portfolio centers on life sciences, green startups, and tech companies, including design marketplace DesignCrowd, integrated circuit-maker g2 Microsystems, and Space Time Research, which (we were somewhat disappointed to learn) is not a time-travel outfit but rather a Big Data startup with an eye on the enterprise.