When a team of Yahoo engineers left the company in 2011 to spin out Hadoop startup Hortonworks, the change wasn’t as stark to either company as one might have expected. That’s because Yahoo didn’t just invest in Hortonworks and let it go on its way transforming the big data technology, which during its formative years was largely developed within Yahoo, into a commercial software product. In some ways, the two companies never really parted ways.

“We more or less virtualized the engineering departments between the two companies,” said Hortonworks Vice President of Engineering Greg Pavlik, in a recent interview. “… There’s a pretty tight overlap between what Yahoo needs and what Hortonworks is looking to productize.”

In fact, Yahoo Senior Vice President of Platforms and Personalization Jay Rossiter noted, “not a week goes by” where engineers from the two companies aren’t getting together and working closely on building new Hadoop technologies or improving the…