I was surprised to see my Google Chrome launching a separate process for each newly opened tab. Actually I was under the impression that it was a bug as Chrome was in beta. But today I found this interesting piece of information, on Chrome site itself which explains that this behavior is intentional.
Google Chrome has a multi-process architecture which makes each opened tab run in a separate process rather than a separated thread.
I used the following simple HTML document to check this out.
var w = window.open();
w.opener = null;
w.document.location = "http://www.google.com";
I could observe on my Windows Task Manager that clicking the "Launch Google" button opens up Google on a new tab, that runs in a separate Chrome process.