It was an exit of epic proportion: Subrah Iyar, co-founder and former CEO of WebEx, sold his company to Cisco for $3.2 billion in 2007. Since then, he's been somewhat of a Silicon Valley phantom, until, that is, a combination of ideas from some of his former WebEx colleagues and input from his college-age daughter inspired him to return to his start-up roots.

The blogosphere likens his new social collaboration tool, Moxtra, to something that's "part Pinterest, part Evernote, and part Facebook," but Iyar says his first creation, WebEx, was all about collaboration so it only makes sense that he use his domain expertise to create something geared for mobile--a contemporary requisite.

In short, he says Moxtra doesn't copy any other solution, he says, but merely appeals to those who prefer visuals over text.

While you can certainly use Moxtra all by yourself in an Evernote-sort-of-way, collecting things like movies, photos, notes and other digital content, the platform shines as a method of keeping groups of people on the same page.

Moxtra makes use of virtual binders, similar to what you might use in the physical world. For instance, imagine a home remodeling project that involves multiple individuals--you, your spouse, a contractor and several subcontractors. Instead of pulling out paper plans, marking them up and having to show them in person to whomever needs to see the changes, everyone can use their iOS devices or a browser to see the latest revisions, copies of materials receipts, things like photos or videos you found online that show how you'd like the finished project to look, and even voice annotations if using text is too cumbersome.

As for Moxtra's CEO, you'd think following in the shadow of what he did with WebEx would be daunting, but Iyar says there's good reason he's banking on Moxtra. Here's what he told me.

You've been almost completely out of the spotlight since you sold WebEx. What have you been doing?
When I sold WebEx in 2007 my daughters were 13 and 15 and you can imagine I had not paid as much attention to them as I should have, so I would almost say No. 1 for us was family bonding time, traveling, teaching them to drive--all of the important things.  Now they are 20 and 18. My elder daughter is doing her last year at King's College London and the younger one just got into Berkeley.

I also helped in the transition of WebEx to Cisco and with some of their strategic vision.

And then beyond that I focused on health for a period of time, family back home, which is India. Playing around with investing in different businesses. I invested in a couple movie scripts, believe it or not. Some tech start-ups. I was slowly sucked back into tech through investments.

How did Moxtra come about?
I kept getting hit for investments in the collaboration space or sometimes it was investors asking for my opinion on the subject. This is a confluence of some of that, some of the thinking that happened over the years at WebEx, just being in that business. But really, it came about because I challenged my older daughter to think about about what collaboration tools she would use, because one of my disappointments was WebEx was still not available to her as a student because of the expense.

So she came up with this concept of binders. It was sort of embedded in this concept of a social network for student groups or study groups, which was very interesting.

Around the same time I met with my co-founder Stanley Huang and he and others were working on next generation collaboration around mobility. So Moxtra was really a confluence of some of those ideas.

So I put in some money and it just grew from there.

How does it work? I understand it's something like Pinterest mixed with Facebook...
Well that is how some of the press have characterized it. Obviously it didn't come from trying to be any of that. We always were very interested in the shared workspace and how we work together.

As I mentioned, my daughter came up with this concept of binders. They're different from folders to the extent that you throw in all sorts of different media and then share the content with your study group and people mark it up. 

The end result is a very visually compelling environment for the collection and assembly of information and digital content. It resembles paper but gives you the ability to do voice over, because so many times the information you're dealing with is visual and for you to describe it in text is difficult.

Would you call it a social network, or not?
I don't like these labels because the definition changes and people define it differently. 

Is it a social network in and of itself? Yes, I mean it is centered around the person and whether we realize it, we live our lives in projects. We've got home projects and we've got sending your kids to college projects and we've got the wedding project and going on vacation at the end of the year project. Besides, of course, all the business projects that people have. And there are people that you work with and collaborate with and interact with around those projects.

Some of the social networks start with people first and projects second and I think this is the reverse--starting with projects and then the people who are involved in them.

So is that social? I think so.

What have you learned since you sold WebEx, and what are you doing differently this time?
The game has changed. When I started in the late 90s, it was all about the Internet. Now it's about mobility. It's about the social revolution. So there are a lot of things we have to rethink and that's very interesting to go back to the drawing board and see what applies now and the way you go to market, the way you position and present your product, your price points. Everything is going through a dramatic change. And so there are a lot of new opportunities and there are a lot of risks and pitfalls if you just do what you did before.

How are you going to monetize Moxtra?
Initially we're saying a person can have 20 binders or 2,000 pages. My idea is to make sure that educational users like college students, who were the original target, should be able to use Moxtra for free.

And after talking to business users and others about the site's extra capacity and security capabilities, such as the ability to protect and track where documents go, there's a lot of opportunity for monetization in the future, but the real focus now is to get the initial user experience really good so people love it.

Is it daunting to do another start-up after the success you had with WebEx? Do you feel pressure to hit a home run again?
Not really. My role at Moxtra is much more of a mentor providing direction for the next generation of leaders. My co-founder Stanley Huang and team are very talented and motivated to make Moxtra a huge success. Given our experience and our complete focus on pleasing our users makes me very confident we will be successful.