Chrome: Split Screen takes advantage of the expansive view offered by wide-screen monitors and splits the viewing pane into two separate panels for side-by-side browsing.
Sure you could go to the effort of opening a new Chrome window and sizing them both to fit on the screen side-by-side but it's not worth the effort with lightweight extensions like Split Screen around. Install the extension, click the Split Screen icon in the navigation bar, and you're presented with a dual-pane browser—as seen in the screenshot above, click for a closer view. Each additional click of the Split Screen button creates a new dual-pane tab—you can't go back to single pane in that tab once you've made it dual-pane.
It's a simple extension—no configuration menu to speak of—but it's effective for the intended purpose and brings you side-by-side browsing with a single click. If you're looking for a similar extension for Firefox check out previously reviewed Split Browser. If you'd like to forgo extensions all together and keep things browser-agnostic, check out the screen-splitting bookmarklet Dual View. Have a favorite extension to share? Let's hear about it in the comments.