Magento

From the demo store you can add an item to the cart by clicking on the following link:

http://demo.magentocommerce.com/checkout/cart/add/product/51/

I think there should be some way to add a quantity parameter to this link.  For example:

http://demo.magentocommerce.com/checkout/cart/add/product/51/quantity/2
or
http://demo.magentocommerce.com/checkout/cart/add/product/51/#2
or
http://demo.magentocommerce.com/checkout/cart/add/product/51/2

Not sure the best implementation, but I think it would be useful.

http://demo.magentocommerce.com/checkout/cart/add/product/51/qty/2

Turns out you guys have thought of everything.  Keep up the great work!