The company suffered a setback in its patent dispute with Oracle last week when a U.S. judge to keep an internal Google email out of the case record. The email, written by a Google engineer, could suggest to a jury that Google knew it needed a license to use Sun's -- now Oracle's -- Java technology in Android.

Ironically, considering this is Google, organizer of the world's information, the email might never have seen the light of day if the search tools used to identify documents covered by attorney-client privilege had done their job, legal experts said.

The incident also shines a light on an area of technology -- electronic discovery -- that's creating big challenges for lawyers as more communication moves online. And it helps explain why Hewlett-Packard is willing to spend US$10 billion to buy Autonomy, one of the biggest providers of e-discovery software and services.

The Google incident apparently stems from a mistake by one of the top law firms it hired to fight Oracle's lawsuit, which accuses Google of patent and copyright infringement in Android. It's a high-stakes case that could potentially cost Google billions of dollars in damages, and force it to start charging handset makers a license fee for Android.

Like many corporate lawsuits, this one began with a discovery phase. Each party is required to identify all the emails, chat logs and other documents relevant to the case, and produce them for the opposing legal team. Because there are often millions of documents involved, they use software tools to define date ranges, search for keywords and find the material they have to produce.