I have a question about Silverlight on the Client Side.

Silverlight is designed differently where it is not possible for a silverlight program running inside a browser can have access to a user's hard drive.

This is a good thing and is important for security.

But there are times when it might be a good idea to save some settings on the client side.

I kind of remember that there is some sort of protected space for that.

Does anyone have any ideas?

I think what you are referring to is Isolated Storage, it's under Documents and Settings, or Users.

I don't see the need to store on disk very often though, it's better to store things in the database - also easier to do your security, and scale.