Note: This ONLY affects NEW products that are created. It will NOT update existing products. If you want to change product attributes for existing products then the product attribute must be included in the CSV file. This can be a great way of defaulting a product attribute to a certain value, but then allowing that value to be changed in the Magento Admin without overwriting that change. Since there are certain fields that are required when creating a new items (ex: Status) this is a perfect example.
Instead of adding the [product.websites] field to the import file it is MUCH easier to use the default value feature of the uRapidFlow Import Profile.
When configuring the import profile go to the Import Columns section.
Select the Field Source Websites [product.websites] and then click "Add New Columns"
Then Select the Values in the "Default Value" column that apply.
If you are not sure what websites the Default value corresponds to go System/Manage Stores
Click on the Website Name
You will then see the Code for that particular website