Many Google Chrome features aren't enabled by default because they're not ready for the primetime or they're too advanced. Unfortunately, you can't enable them from the interface and you have to use command-line flags.
A recent Chromium build added a new internal page that lets you enable some advanced features: about:labs.
"Tabpose is currently the only lab on the Mac, tabs-on-left the only lab on Windows. about:labs should not be visible on the stable channel. Labs that were enabled on the dev channel should not be enabled on the stable channel."
Tabs-on-the-left is especially useful on the widescreen monitors, while tabposé is a Mac-only feature that adds Exposé for the tabs.
Both features can also be enabled by adding the command-line flags to a Chrome shortcut: --enable-vertical-tabs for the side tabs and --enable-expose-for-tabs for tabposé. After enabling vertical tabs using the command-line flag, right-click on a tab and select the "use side tabs".