Today Google Adwords announced that they’re adding to the existing conversion tracking options in order to allow you to better track campaign performance.
If you’re solely a lead generated business then these new options won’t effect you very much since you’ll still want to focus on each visitor as a unique conversion. If you run an online store however and also acquire new customer leads through techniques such as free e-books, chats, etc. then this change will be a huge benefit.
Before you could track unique conversions, but you were limited to looking at all conversions essentially as 1 per click or multiple per click. Now you can specify certain conversions as one per click and others as multiple. Here’s an image from Google which better explains it: