I have recently discovered via google webmaster tools that I have over 900 duplicate meta descriptions. After some digging around, I found out that when you leave a meta description blank, Magento fills it with the product description.
In most cases this probably makes sense to do. However, in my store, I have a huge selection of a type of product that is almost exactly the same except for maybe a color or a slightly modified wording. Because of this I intentionally left the meta descriptions blank since it is simply not an option to write unique meta desc tags for all these products.
So with magento auto filling these with the product descriptions which are duplicate, it is causing a big problem. Is there a way to stop magento from auto-filling. If not, the next best option would be to remove the meta description tag altogether on product pages only.