#whoislive

What if every web page you visited became an instant chat room? Startup WhoIsLive is launching a browser plugin Tuesday that could become one way to find out.

The Internet Explorer and Firefox plugin creates a browser sidebar that shows you other users who are looking at the same web page. Using the sidebar, you can set a status message that everyone else on the page can see, or you can chat with people individually.

Theoretically, the tool can show you who is viewing your Facebook profile, allow you to ask for guidance from other shoppers on an ecommerce site or be used as a real-time discussion tool on blogs and news sites. The websites’ publishers don’t need to install anything for the plugin chat room to work on their sites.

But there is one rather huge caveat: Users can only see each other, not web browsers who haven’t installed the plugin — which means that a critical mass of users needs to be reached before the tool is useful. And before you can see who is viewing your Facebook profile, you’ll need to make yourself visible to people who might be monitoring their profiles with the same tool.

“It’s like anything else that is related to social,” explains co-founder Elad Natanson. “It’s a give and take. ”

The idea behind WhoIsLive is a great one. Companies like Marginize have long been aiming to build a social layer on the web that is based on what you care about instead of who you know, and enabling people on the same page to connect is a smart way to do it. If the tool gains widespread adoption, then Natanson’s prediction that WhoIsLive will “change the way that people use the Internet” isn’t unreasonable.

Getting to that critical mass, however, is the startup’s biggest hurdle. If it pulls it off, Natanson says WhoIsLive will sell a premium product to site owners that designates them as such in the chat list. Many services like WebsiteAlive and Livezilla offer similar live-chat customer service tools, but site visitors can onlychat with the site owner. The premium product would also offer site owners personalized analytics.

“You always see the numbers,” Natanson says. “But in this case you can actually see who your visitors are … You can connect with them.”