Ever since Google launched the web-based Play Store, it has been iterating rapidly to improve the experience. Now that there are more apps in the store than you can shake a phone at, you're more likely to run into one with a description written in a language other than your own. With that in mind, it's pretty cool that Google has chosen to quietly deploy Google Translate in the Play Store.
If you land on an app listing in another language, you might see the Translate bar right above the description. It will read, "Translate the description into [LANGUAGE] using Google Translate?" In this example [LANGUAGE] is replaced by whatever your default language happens to be.