I modified my website slightly so that links pointing to an item submission of some sorts (such as the "add item to shopping cart" link) are now submit buttons. For example:
<a href="http://example.com/item123/buy">Add to cart</a>
To something like:
<form action="example.com" method="POST" enctype="multipart/form-data"> <input type="hidden" name="ItemNo" value="123"> <input type="hidden" name="Action" value="buy"> </form>
This comes with two advantages. The button click doesn't go to a cached page, meaning data is actually being submitted, and seeing that I've applied this change to over 500,000 pages and I changed 4 links to 4 buttons, Search engine spiders will now have to only scan 500,000 pages as opposed to 2,500,000 pages.
The only thing I can think of which might be a problem is ads inside those pages after the button is clicked.
So now I'm curious. I looked at my performance stats, and my RPM was averaging out at 7 cents RPM and now today after the change its at 0 cents RPM. I know people say that RPM means that's what you make per 1000 users, but I think google is evaluating it much differently.