According to Techcrunch, Lob has raised $20 million from Y Combinator's Continuity Fund, and former Twitter COO Ali Rowghani is joining the company's board. Lob today, alongside its snail mail business, is also launching a new service that will help businesses verify that certain addresses exist. So anyone trying to ship a package -- and make sure a human actually exists at the address -- or just trying to figure out that a person lives at the correct physical address could also in theory be a Lob customer without actually having to use its core mail delivery business. Lob had to go through a certification process with the U.S. Postal Service to ensure that it was able to get access to that address data, co-founder Harry Zhang said.

"If you're shipping something through an address customers type something wrong, if it's not correct, they need to make sure it's verified," Zhang said. "The problem is they're going through a lot of operational overhead to start creating the mail and then finding out after the fact the mail and packages aren't actually deliverable. If they can pull to the front and set it up so you enter your address and say 'hey did you mean this,' that's a better experience."

Businesses provide the address and content in a form like HTML, which is then passed through Lob. The company then makes the mail at a location closest to the final destination of the recipient, gets it over to the U.S. Postal Service and it's on its way like any normal piece of mail from there. By doing that, Lob is able to ensure a quick delivery and also let its business customers know where those pieces of mail are at any time.

Many businesses may also have to use normal mail for compliance reasons, which can vary on a state-by-state basis, Zhang said. For example, some insurance cancellation documents have to be sent through mail, Zhang said. At a scale of millions of people, it may be easy for a letter to simply get lost or not make it to the correct person -- or just sit on a desk somewhere -- and Lob's goal is to get some insight into how to ensure that mail gets to the right place.

Zhang said that mail is indeed not dead -- and it's probably not that surprising given that the massive population of the U.S. may or may not be interested in getting a normal letter. Part of it may even be that people appreciate the emotional reaction and tactile feel of a letter, he said. But Lob has delivered mail to one in nine households to date, he said.

Lob isn't alone in offering businesses a way to print and send things through snail mail. Though a sort of different approach, Kite.ly -- which was acquired by Canon in March -- gave businesses a way to print things on their webpages and send them. And it's always possible that Amazon or any other businesses that wants to own the operations segment of a business, which Zhang hopes Lob will own, will jump into it. But the hope is not to just stay with mail, and eventually build a whole suite of products around peoples' addresses and getting the right things to them in the physical world.