i know this is an old post but I'd like to also vote for a referral system.  I can't find anything in the extension store which works like the referral system in Prestashop.

Hi, just to add to this I just had a customer call to ask about adding multiple items.  They just wanted to be able to click multiple times to add more product to the cart but with the html5 template once clicked the button says 'added to cart' then if clicked again takes you to the cart (where they can increase quantity).  This behaviour annoyed my customer.
I also notice there is a little x in the corner of the price tag once a product is added a per the above scenario.  clicking on this little x does nothing but if I inspect the element in my browser it shows as <button class="close" data-dismiss="alert" type="button"> which seems to indicate that the button should be 'dismissed' and return to normal??
Anyway, I still think it would be great if in grid view the customer can either have a quantity option or be able to click the button multiple times to add more product to the cart.

+1 for this.  Ebay integration will get Abantecart onto the radar of those using Magento and Prestashop which offer ebay integration already.

Thanks for the suggestion junkyard.  I actually discovered another way to do this which is easier for me as my sql skills are limited.

In admin under System | Data | Import / Export I exported some line items (for a test sample).  I opened these in LibreOffice Calc (I use Ubuntu as my OS - LibreOffice is an open source MS Office alternative with LibrOffice Calc = MS Office Excel).  In Calc I create a new column next to the price column and use the formula =SUM(M2*0.9) (where M2 is the column where price is.  I then just replace the price colum with the values in this new column, delete the new column, save the file as csv, then import back into Abantecart from the admin menu.  It updates all pricing to 10% less.

Another way to do this would be to create a new column and then use the Cost column to add the desired percentage then replace the Price column with values in this new column. Just depends which way you want to go, reduce prices by a percentage, or do a recalc adding a percentage to the cost price.

In fact doing this makes it faster to add new products.  I can now add products and just put the cost price, then when I'm finished I do the export, do a bulk calculation to add my percentage as per above, then import.

I hope this helps others.  Or if anyone has a better way I'd love to hear it too.

Yes, I meant on the product listing page.  Just to make it easier for those who know what they want (they don't have to go to product details page).

I'd like to +1 this idea.
I sell food products and would iike to have the main category (say grains) then allow the customer to filter the list such as Gluten Free, organic, etc.

Many ecommerce sites have a small text box to input a quantity beside the 'add to cart button' rather than having to click multiple times.  Good for if someone wants to by larger quantities of a product (like 10 or 100) as that is a lot of clicks otherwise.