In the old days, people used to set up an office by buying a printer, a scanner, a faxer, some chairs and tables and a phone. But all that has changed for large portions of the population, he explains.

“The difference is that now is that you have your laptop and your phone, and you don’t work there. You work everywhere. So interactions with paper become especially painful. And that’s the premise of the whole company. You have all these painful interactions with paper, and so how do you solve them?”

Walla is reluctant to give specifics on HelloFax’s material success, but he said the company is growing rapidly and doing well, expanding from its small offices in San Francisco’s Lower Haight neighborhood and constantly considering potential new products to spin out. Walla said companies nationwide are using HelloFax, and the company launched a companion product, HelloSign, this summer. Google included HelloFax as an initial partner when they launched Drive this year, and Monday, HelloSign will be integrating with Drive as well, allowing customers who download the Chrome extension to sign their Google Docs using the service.

At a basic level, the Google Ventures-backed HelloFax lets users to send and receive documents without ever touching a fax machine, and it’s catching on with the legions of tech-savvy individuals who are still asked to fax documents every week. Walla said one of the greatest challenges in working with people to digitally sign or fax documents is that it’s generally a low volume business. How often are you asked to fax something? So integrating with products like Evernote, Box.net, Dropbox, and the recently-announced Google Drive has been key to win large-scale consumer adoption. Walla said that when HelloFax integrated with Google Drive, it initiated more than 170,000 installs.

At 27, Walla isn’t your typical Stanford engineering major-turned-YC-startup-founder. In fact, he doesn’t even do much coding. Walla grew up in Minnesota and attended the state’s flagship university, winning both the prestigious Truman and Luce scholarships. He did stints with the U.S. Embassy in Rome, anti-human trafficking efforts in Thailand, and conflict analysis in Switzerland, before becoming a a finalist for the Rhodes scholarship. He wasn’t ultimately selected, and began thinking of doing something less bureacratic than public policy, so he started HelloFax at home in Minnesota. Later, when he flew to the Valley for a job interview, he canceled the return portion of the trip and decided to stay.

Walla recruited his co-founder, Neal O’Mara, by posting an ad on Hacker News, and O’Mara joined HelloFax shortly before his previous company, TripIt, was acquired by Concur for $82 million. That same winter, Walla and O’Mara were accepted into Y Combinator, and HelloFax began to take off, presenting at YC demo day in March 2011.

I asked Walla what the company’s future will look like when faxing eventually goes out of style — it’s not exactly an evolving technology. But he pointed out that faxing is still incredibly popular in places like Europe and Japan, and helping consumers who need to interact with fax-happy co-workers will probably last a long time. Industries like real estate and finance still very much rely on paper documents.

But even when faxing eventually goes out of style, he’s not worried, pointing to HelloSign, the company’s newest iteration challenging the likes of EchoSign and DocuSign as another bright spot in the company’s future.

“It will die, it’s not the future. And we’re okay with that,” he said, then putting on his public policy hat: “But signing documents will be around forever. We cannot have society without agreements.”

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