AppExchange is a marketplace for cloud computing Web applications built for the Salesforce.com community and delivered by ISV partners or by third-party developers. Apps from the AppExchange can be installed to any Salesforce environment. AppExchange Apps can be free to install or may have a subscription fee.
Launched in 2005 AppExchange is a marketplace for cloud computing Web application, As of April 2012, there are over 1,400 applications available from over 450 independent software vendors. All salesforce.com ISV partners can distribute applications and solutions on AppExchange. Applications created on the Force.com platform are installed by Salesforce.com customers.