Canvas functionality is a new technology from salesforce.com for force.com platform. This functionality allows direct communication between salesforce’s visualforce pages and third party applications. Browser does not allow to communicate between pages from different domain by default as it is security issue. Canvas from salesforce.com allows support such type of communication, what is its advantage. [...]
This solution used Apex scheduled class to establish integration between Salesforce.com and a 3rd party order management solution. By levering Apex, we were able to avoid using 3rd party middleware which would have been more costly for the client.