Customer Portal - What Customers See

Customer Portal - What Customers See

Hi Folks, 

We are looking at implementing the customer portal for our customers.  When using the customer portal, do customers see only records that are their own, or can they see all records?  

We work in a fairly sensitive area, so we want to only allow customers to see their own records, not all of the records on the system.  

Can you please let me know if this is possible and how we set it up so customers can only access their personal records and not all records? 

Also, is there a trial version of the customer portal so we can see what it looks like, test the functionality and make sure it is the right solution for us? 

Thanks!