Why you'll be hearing 'Hadoop' a lot in 2015
Source: Doug Cutting · CNBC

Get ready to hear this word a whole lot in 2015: Hadoop.

Silicon Valley has long been buzzing about it, over $1 billion of investing dollars flooded into related start-ups this year, and tech giants like Intel (INTC) and Google (GOOGL) are betting on it.

But what is it? The stock market will get its first real taste on Friday, when Hortonworks (HDP), a seller of Hadoop technology, debuts on the Nasdaq under ticker symbol HDP. The Palo Alto, California-based company raised $100 million Thursday night in its initial public offering, selling 6.25 million shares at $16 apiece.

Hadoop is a challenging subject for anyone who doesn't spend their days thinking about enterprise software. Here's an oversimplified explanation of Hadoop and how it's grown into something meaningful and potentially massive.

Read More Hadoop: Toddler talk provides big name

In the early-to-middle part of last decade, engineers at Google and Yahoo (YHOO) were developing software to improve search results and better understand all the crazy amounts of information that queries were producing. That technology became part of an open source project, which later became Hadoop. The code is housed at the Apache Software Foundation.

Over time, Hadoop spread well beyond search and became a central tool for some of the biggest consumer Internet companies, including Facebook (FB) and LinkedIn (LNKD), to make sense of the tons of unstructured data sitting across many machines that were flowing through their network. Companies using Hadoop internally would contribute their own code to the project.

Then the business opportunities started to become apparent. Imagine if e-retailers knew more about their customers, or if medical companies could better predict a patient's risk for specific diseases or if advertisers could more precisely target the right audience.

"The Hortonworks opportunity is to enable Hadoop to be an enterprise viable platform for managing all of this data within the enterprise," Chief Executive Officer Rob Bearden said in the online roadshow before the IPO.

But other start-ups got there first. In 2008, a group of data nerds from Facebook, Google, Yahoo and Oracle came together to start Cloudera and began evangelizing the benefits of Hadoop to anyone who would listen.

MapR was formed a year later to also find commercial applications for Hadoop. And in mid-2011, Yahoo joined with venture firm Benchmark to form Hortonworks as an independent company that would "enable Apache Hadoop to meet the growing market demand and become the big data management and analysis platform of choice for the industry," according to a press release at the time.