What are the most effective and most popular e-commerce tools? I think the shopping cart kind of scares people away but it actually works and opens the possibility of buying something when browsing. I also think that probably advertising in every available site is not that positive for any product.
Shopping carts are a convenient way to let people buy multiple things on our site at once.
If you have a large site with many products, then the shopping cart is best. However if you have a small site with only a few products, then there isn't any point and they just confuse the user unnecessarily.