Social publishing network Wattpad today announced that Toronto's OMERS Ventures has joined its existing Series B round of investment, which totals $17.3 million, the amount announced back in June (OMERS participated in that amount, but hasn't officially been on the books until today). The addition of OMERS adds to the company's strong existing portfolio of investors spread across a number of geographies, including Khosla Ventures in San Francisco, Union Square Ventures of New York, and Golden Venture Partners of Toronto. Wattpad, originally launched in 2006, has attracted huge engagement with its social network for authors and readers. All content on the site is free, and creators work together with readers to receive feedback and work on longer pieces a chapter at a time, incorporating input from others to change the direction of the story as it evolves. That's proved attractive to users, who have contributed over 6 milllion stories at a rate of around 900,000 new ones per month, from over 10 million unique monthly users. Those users now spend double the time on the site they did just six months ago, according to Wattpad, at 2.4 billion minutes per month. For its part, OMERS Ventures has become one of Canada's most active VCs. The firm's portfolio is growing, with investments in AppHero, Wave Accounting, Hootsuite, Hopper and more, all coming within the past two years. OMERS is also a key investor in a number of accelerators and incubators, including Extreme Startups, and that's an important ingredient in terms of their value as a strategic partner for Wattpad, CEO and founder Allen Lau tells me. "Most important to us is hiring," Lau said, highlighting that Wattpad's growth has prompted a continuing need for engineering talent. "Locally, we're getting a higher and higher profile, and we want to attract the top talent. Having OMERS, who has access to all the top accelerators, incubators and university programs, we'd be able to tap into that network." Wattpad's focus is heavily on product and on continuing to develop it in order to feed and foster growth. Lau believes that Wattpad has one thing that other social networks like Twitter don't, which is helping its growth accelerate the longer it sticks around: a content base that's more permanent and evergreen. Wattpad's stories aren't nearly as fleeting in their value as individual tweets, and so the relative value of the Wattpad network grows as its library gets bigger and bigger. That's helped really push up the engagement numbers, Lau says, especially with regards to time spent on site. As Wattpad continues to grow, it really is becoming a quiet storm gaining in mass and a testament to taking a more patient approach than most to building a company. The company still isn't seeking revenue from users, and how it eventually chooses to go about doing that is still under consideration. But the focus on engagement first seems to be paying off so far, at least in terms of attracting attention from noteworthy investors.