Customer Interface Reporting / Portal

Hello, What are people using to provide customer interface usage reports to customers? There seems to be lots of RRD based tools that can gather the data and store it for long term viewing. We use ZenOSS for internal purposes for example. How do we go about providing each customer access to their data in a secure way? A portal type access. Is anyone aware of a tool that includes a front end that can partition the data on a per customer basis? Each customer would have their own login ID and only see their data? How do we link the data to that customer? Some customer ID on the interface description? Thanks, Serge