I don't get it. I create an extra field called URL_field, and another called LinkText_field. Now let's use designerweb's example (but assume for simplicity's sake that it's one link per product):
"For example, if I am selling a chair. On that chair page I would
like to place a link to a page that help customers polish their chair".
Okay, so for product chair URL_field contains the url to a page on how to polish a chair and LinkText_field contains "how to polish your chair".
"And on my Table page, I would like to add a link on how to polish tables."
Okay, so for product Table extra field URL_field contains the url to a page on polishing tables and LinkText_field contains "how to polish tables".
Now for each product, there will be a place for such a link. If fields are empty, the code says do not display. If fields for product not empty, then the code displays <a href="URL_field">LinkText_field</a>.
What does it matter if a product is discontinued, removed, or something else? This code will be in a product template page, and if the field values are empty, it will simply not display anything ? So what am I missing? As far as I understand these links will not be to other products?