Weebly, the web-publishing startup founded by Penn State graduates David Rusenko, Dan Veltri, and Chris Fanini, is now valued at $455 million after receiving funding from Chinese internet giant Tencent and California-based venture capitalist firm Sequoia Capital to the tune of a cool $35 million.

Rusenko, Veltri, and Fanini co-founded Weebly while studying at Penn State back in 2006. Back then, students were required to maintain an online portfolio, so the trio of 22-year-olds created software that made it easy to build and maintain a website.

“When we were getting started, we’d work all day and night until the light came up, and we’d crash until we’d had as much sleep as we’d needed, and then we’d wake up and just start working again,” Rusenko told students during his appearance last week at IST’s Startup Week.

“For about two years that was our working schedule,” he said. “It wasn’t until about 35 months in that we became profitable, and not until around 48 months that we were really off to the races.”

After completing early-stage development as part of the winter 2007 class of YCombinator — the prestigious startup incubator that provides money, advice, and connections in exchange for six percent of the company’s equity — what became Weebly’s easy-to-use drag-and-drop interface quickly attracted millions of users.

The company now hosts more than 20 million sites that are seen by 175 million visitors every month, putting the company in the same echelon as top website-making groups like WordPress and Squarespace.

“You can’t succeed if you quit,” Rusenko said to a packed crowd at IST. “There will always be obstacles in the way, and the only way you’ll be successful is through sheer determination.”

Even with the company now worth nearly a half a billion, Rusenko doesn’t sound like he plans to stop anytime soon.

“And now, I’m incredibly proud of how we’re able to help people take their dreams, their vision, and make it a reality through our website,” he said. “But there’s still a lot of work we want to do. The story isn’t finished; the ending hasn’t been written.”