These days, finding ways to have your store pages pop up in a Google search can be crucial to helping improve sales. You probably already know that you can use the Title and Meta tag fields on the category and product display forms to try and help search engines give your pages better page rank (if you don't, go back and fill those in!). But there's another very important piece to the puzzle. Google also tends to check for duplicate pages that have similar content and only list the one they consider most relevant.
Now, this can be helpful if for instance your site has both SES links and regular dynamic links to the same pages. Google is pretty smart about picking the SES page to index, particularly if it has keywords in the URL. But where this can become detrimental is if you have products in your store that are commonly sold elsewhere. Let's say that you don't feel like being bothered coming up with your own product descriptions, so you just paste in the ones created by the product manufacturer. Here's the problem...other people do this as well! Now there are many URLs out there with the same product descriptions. To Google, these may look like duplicate pages...and yours may end up being the one they drop!
So while it may be a bit of a hassle to do, if you are using products in your store that may be listed elsewhere, be sure to try and include a fair amount of unique content on your pages to ensure that they get properly indexed.