Google Inc. (NASDAQ:GOOG) has released some stats about the Apps Marketplace. About 4 million Google Apps users have downloaded at least one Marketplace app and installed it on their domain. Google launched the Apps Marketplace back in March.
To set up a Google Apps Marketplace App on your domain, you can use a set of APIs or third-party apps. Some of the apps are free and some are paid. Apps that are popular in the Google Apps Marketplace include Zoho, Socialwok, Bantam Live, MailChimp, Insync, and myERP.com.