I was trying to think of practical examples for needing to pass a value with a hyperlink. I've been doign HTML for a few year btu never needed to do that. I was thinking of when I visit a retail site and how pressing the "Add to Cart" button causes there to be a one in the text field next to the name of my product. Is that correct? Are there other practical examples of passing values with links?

Thanks for your help and time.