Thanks for responding. Regarding your first question, how do I know the item will not be in stock, here is an example:
http://www.kaboodle.com/reviews/sparq-xlr8-digital-timing-system
That item was discontinued five years ago. If you click on the "Buy It Now" button, you will notice that it links to a url that is no longer maintained. I receive many inquiries about this product because it is similar to our line of products, so I wrote an article that not only discusses the product, but also mentions that the product was discontinued years ago. The article ranks well, but many people are frustrated by these stale links on other sites. I've contacted some of the shops that have stale links to clean things up though it does require considerable effort. It just seems that Google should be better at spotting these dead products, especially when "buy it now" points to a dead site.
Thanks again for responding.
Best,
Christopher