The Web site Feld.com, which has the Marginize widget installed. This means anyone can join the discussion on pages like this one and others with the widget.

PALM DESERT, Calif.--Since the beginning of time, or at least since the beginning of the Web, we've all used Web sites in solitude, regardless of how many social tools were available.

But thanks to an application called Marginize, that dynamic may soon change. At the Demo Spring conference here today, Marginize talked about how, for what may well be the first time, social and collaborative Web browsing is finally here.

The idea is actually quite simple. Using either a browser add-on--for Firefox, Chrome, or Safari--or a native application on sites whose publishers have opted-in, Web surfers can now see what other people are saying in real-time--on services like Twitter, Facebook, and Google Buzz--about the pages and the topics they're exploring.

Until now, said Marginize founder and CEO Ziad Sultan, people have been able to talk all they want about what they're seeing on the Web, but have been limited to doing so in "social silos." Marginize, by comparison, aims to bring the conversation about a page right on to that page. A simple window that pops up when you click on the little Marginize tab that sits on the side of the page shows the real time discussion around the topic, and gives users the ability to easily jump into that conversation by tweeting or posting to Facebook or by responding to what others have already said.

For several months, a group of users has already been applying Marginize to more than half a million sites, Sultan said. Those beta users have each downloaded the browser plug-in and employed it to bring the service's social aspects to sites in which they are interested. But that didn't do anything for people who haven't downloaded the add-on, let alone those who haven't even heard of the service in the first place.

At Demo today, the company announced the launch of its publisher widget, which makes it possible for owners of sites of all kinds and sizes, from personal blogs to large news sites, to proactively place Marginize functionality on their pages. Now, for example, Brad Feld, who writes about entrepreneurship for Boston.com, has the Marginize widget embedded in his page, allowing anyone to see and participate in the ongoing conversation taking place on his page.

There's no doubt that in order for Marginize to be truly useful, it needs a large critical mass of users. After all, there's not much point to looking for a conversation that isn't there because there aren't enough people discussing a page or its topics. But if the company can lure in enough users, and enough sites embed the tool, there's a real chance that it could permanently change the way we interact with Web sites.