Flush with $70 million more in venture cash and a $1 billion valuation, Evernote has made another modest acquisition. It is buying digital handwriting app Penultimate – the fourth highest selling iPad app in history.

Penultimate is basically what you buy if you own an iPad, and you’re not looking to fling pissed off birds around via sling-shots.

While this isn’t exactly a blockbuster deal for a company already laying the foundation to go public, the move will appeal to die-hard Evernote fans who’d like to see better handwriting integration throughout the app. Count Evernote CEO Phil Libin as one of them.

“It’s just a beautiful application,” he gushed on the phone to PandoDaily last week.

Libin has known Penultimate founder Ben Zotto since the app’s earliest days. As a company, Penultimate has been the inverse of Evernote in many ways. Libin always had a grand we’re-building-a-company-for-100-years strategy and raised plenty of money to get there.

Meanwhile, Zotto just built a handwriting app for the iPhone because he wanted one. A few of his friends used it. And then, when he saw the iPad, it hit him — this was the piece of hardware his software had been looking for. He rushed an iPad version into the app store a few weeks after it came out, and it has steadily grown since. Despite selling millions of apps, Penultimate has remained a scrappy, one-man bootstrapped operation.

Penultimate and Evernote have a similarly yin-yang product relationship, Zotto said in a call with PandoDaily. Evernote has long had technology to recognize and search handwriting, while Penultimate has software to enter and capture handwriting onto the iPad. “What it does now is push handwriting into the Evernote soup and makes the handwriting searchable,” Zotto says of the existing integration with Evernote’s APIs. “But it doesn’t come back into Penultimate.” That’ll change with new resources, Zotto says. Zotto will join Evernote as an employee as well.

Zotto will also be able to get to a huge list of features users have been requesting — that includes Penultimate being developed for other platforms. “When you’re bootstrapped you have to pick your product roadmap carefully,” he says.