From middle school girls’ sleepovers to more codified groups like the “Ladies’ Four O’Clock Club,” women have known for ages that there’s something special about the conversational dynamic that happens when a group of females get together. When women are with other women that they trust, they often can be completely honest and comfortable in a way that they may not be in more mixed company.

A website called Women.com aims to be the go-to place where women can speak honestly with each other online, deliberately away from the male gender — a sort of Ladies Four O’Clock Club for the online world. The bootstrapped startup, which is co-founded by CEO Susan Johnson and CTO Neal Kemp, is launching this week out of the current class of Y Combinator.

Although there are a lot of sites aimed at female audiences that already have strong commenting communities — Jezebel, XoJane, iVillage, the BlogHer network, just to name a few — Women.com aims to stand apart in a few key ways. For one, there is no editorial voice steering the conversation: Topics are user-submitted, making the site a pure community, more like a Reddit or a Metafilter. Secondly, Women.com is more strict than other sites about being only for females, as men are forbidden from logging in to access the site’s content. The gender exclusion is maintained at the moment by the site being invite-only, something that the site’s users take seriously (investor Jason Calacanis received a good amount of backlash when he requested an invitation to Women.com on Twitter). If it becomes apparent that a male has accessed the site, that account is banned. In the future when Women.com launches out of beta, the company plans to verify its users’ gender by using Facebook Connect.

In an interview earlier this month, Women.com CEO and co-founder Susan Johnson told me that she first thought about the potential for creating a safe place online where women can learn from each other and share their experiences and opinions in her college years, when she worked on developing a website called “Savvy Girl.” The concept was put on the back burner, though, as she went on to build a career post-college in marketing for entertainment and digital media firms. But in her most recent corporate role as a marketing executive at Facebook, she realized that her initial dream of a female-only site could still have legs.

“I started really noticing what people were doing on Facebook, and how they were sharing. Even when you know it’s just friends [with group privacy controls], the women I knew were still just posting pictures of their kids, and the vacations they were on — they were just holding back in a way,” Johnson said. But offline, or in an email thread of just girlfriends, Johnson says, “the conversations would just erupt. We’d talk about a mish-mash of topics. What we’re eating, what we’re thinking, what we’re doing. And I thought, ‘Why can’t I have these conversations on Facebook?'”

Johnson says the tone of conversation on sites like Facebook and Pinterest is still affected by the fact that they are co-ed environments, even though online activity is dominated in many ways by women. “The conversation is just different when it’s only women. When a man enters the conversation, the tone and the cadence is just different,” she says. “In terms of engagement, as Aileen Lee says, women rule the Internet. Why isn’t there a place that has been built just for women?”

In August 2012, Johnson stepped down from her job at Facebook and used some of the money she’d earned there to purchase the Women.com domain name, which had previously been owned by NBC and was just a landing site redirecting to iVillage. (Johnson declines to say how much the URL cost her, but prior deals to purchase the domain were in the seven figures.) From there, she brought on Kemp as a technical co-founder, and they set about building the site, which launched in private beta in early June.

At the moment, Women.com has a pretty basic interface: There is one main homepage and several different categories in which topics are slotted, such as Health and Fitness, Family, Career, Relationships, and others. The site highlights one question per day to feature prominently. The site has a lot of breadth: Examples of popular topics in recent days include everything from Kegels, to whether or not to take your husband’s name, to politics, and more.

Right now, the average Women.com user is between 25 to 40 years old. “We are erring on a slightly more mature audience. We’re not deliberately going after the 13 to 24 year old market, at least not yet,” Johnson says. “For now we’ve been focusing on this mystical age range of when you start really identifying as a woman, and having the post-student life experiences.”

Women.com isn’t releasing user or engagement numbers just yet, and Johnson and Kemp say they are deliberately keeping the growth slow to make sure that the site scales effectively, but the small community that is there seems to be extremely engaged and thoughtful: It isn’t rare to see a seven paragraph comment on a Women.com post. In the future, Johnson and Kemp say, the site plans to add more sophisticated social features and channels for topics. Right now, the site experience is very simple — but talking to Johnson and Kemp, you can see how, if executed well, this could turn into something very popular.

And while the range of topics currently being covered on Women.com may seem to err on the less serious side in the grand scheme of things, Johnson says that ultimately, conversation itself can be a powerful catalyst for important changes. “Twitter didn’t start out saying that they were going to disrupt governments. Facebook didn’t start out saying that it was going to bring distant families closer together,” she says. “The ultimate vision is that Women.com can be a safe place for women to create their own dialogue, whether it’s about fashion, or about the fact that women in Saudi Arabia can’t drive. We’re just going to see where the conversation goes.”