Just like Firefox, Google has added add ons for their Chrome browser version 4.0. The search company called it Extensions. Google also added Opera-like bookmark sync function.
From Google blog: Extensions let you add new features and functions to your browser. Some provide one-click access to some of your favorite web applications like eBay and digg, or news and information sources such as NPR and Time.com. Others are useful tweaks for performing common online tasks such as browsing photos, getting directions or shopping.