I generally like to submit product reviews for the items I purchase--because I like getting the points boost--and followed the link in an email I got today to do so. My issue is that it took me to a page showing all my purchases for the past few months--even ones I'd already reviewed. I really think it would be useful to customers to have an easy way to figure out if they've done a review for an item, short of writing a review and having it get rejected as a duplicate after putting that time into it. Searching through some of the 120 reviews on one product like I did today isn't easy, either.
-On the rewards points history, include what product review the points are for. You could do a +/- dropdown box like for purchases.
-When taking customers to the purchase list via the email link, have text indicating whether or not a review has already been done for that product.
-Have a page within rewards that shows "my reviews/reviews I've submitted", just like Amazon does.