??? hook_add_to_cart ???

I was looking at this hook, it might work for my application.

The customer can click a link that simply adds the item to the cart with the attributes value set.

I will experiment with this alternate approach, any help or example will be appreciated.
For example, how to go about it so that the attribute is set when the item is added to the cart and the browser returns to their shopping page (or any other defined url) automatically.