It was only a matter of time before Vringo's (NASDAQ:VRNG) subsidiary, I/P Engine, would go after Microsoft (NASDAQ:MSFT). Vringo brought a lawsuit against Google and others last year for patent infringements on its search engine advertising system -- and won. Now it's taking the same fight to Microsoft and investors are hoping to benefit from another courtroom victory.

When at first you succeed, try try again
I/P Engine successfully won its suit against Google, AOL and others this past November and received about $30 million in damages and will receive running royalties of about 3.5% until 2016. The lawsuit focused on a handful of patents owned by Vringo, created by its now Chief Technology Officer Ken Lang. Since Vringo's patents were upheld in that suit, the company can pursue Microsoft and other companies using the same patent infringement claims.

The new lawsuit focuses on two specific patents, which were filed in 2001, that explain an online search advertising system that is used by many tech companies. According to the official complaint, I/P Engine alleges that Microsoft's Bing Ads system infringes on the two patents and I/P is entitled to damages.

What to expect when you're suing
I/P Engine didn't state specifically in the suit how much it's asking for from Microsoft, so it could be a while before investors know how much Vringo could make if it wins the suit. But whatever the final number turns out to be, investors would be smart to remember that Vringo only received a fraction of what it was seeking in its November lawsuit.

Vringo's stock is completely dependent on lawsuits like this, considering the company is hardly focusing on any other products or services. Investors should expect Vringo's stock to remain volatile depending on news of the suit and the final verdict. Vringo was up 200% in 2012, and is up about 8% since the beginning of January.

Whether the company wins or loses against Microsoft, don't expect this to be the last of Vringo's lawsuits against tech companies. Vringo spent $22 million to buy patents from Nokia back in August, and given its win against Google in November, the company is likely to use those patents to go after companies like Yahoo! as well.

Trolling for returns
Many consider Vringo to be a patent troll, and whether it's true or not, some investors pocketed significant returns with the company last year. I've said before that I'd be wary to invest in Vringo because of its volatility and the fact that its entire business is built on jury verdicts, but billionaire Mark Cuban disagrees; he's the company's largest shareholder with a 7.4% stake. Investors should consider the fact that buying stock in Vringo is an investment in jury decisions and ongoing litigation instead of products and services. If that matches up with your investment thesis, then there may be large gains in your future.

Chris Neiger has no position in any stocks mentioned. The Motley Fool recommends Google. The Motley Fool owns shares of Google and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.