>is it possible to create an application using Sharepoint?
>
>I never used Sharepoint before but AFAIK it is a tool to share documents with some interace. The reason I am asking is a customer looking at our tool said that they are building an application with Sharepoint and want us to integrate his application with our tool.

Yes, absolutely you can build applications with Sharepoint. Here's a place to start learning: http://office.microsoft.com/en-us/sharepointdesigner/HA102390461033.aspx

Tamar