Force.com Sites is relatively known feature which allows SFDC developers to set up public-facing sites/pages hosted by Salesforce platform. Using Force.com Site you can build micro web sites with one landing page or complicated sites with multiple pages. Such sites could have complicated flows to expose/collect information from/to Salesfroce. Advanced Force.com sites could even (for instance) accept credit card payments.

There is wide known scenario when click to APEX command button on custom VF page would take quite long time to perform calculation on server side and return the result back to UI.

There is wide known scenario when click to APEX command button on custom VF page would take quite long time to perform calculation on server side and return the result back to UI.

There is wide known scenario when click to APEX command button on custom VF page would take quite long time to perform calculation on server side and return the result back to UI