The ability to create new and different experiences for users is not just limited to mashups. Using the extendibility and openness of the Firefox browser, it is possible to create "extensions" that can affect the way a site is displayed. For instance, when the Book Burro extension senses you are viewing a book on Amazon.com, it will add a small overlay on the page which, when opened, lists prices at online bookstores such as Barnes and Noble, Buy, Half (and many more) and whether the book is available at your library. All of this is done without the user having to do anything.

Another type of extension is AdBlock. AdBlock automatically eliminates all the ads from a website, and the results are rather astonishing. Just look at how The New York Times site looks with AdBlock installed.

If you are displaying ads on your website, do you know if your ad impressions are different from your page impressions? Do you know how customers are looking at your website? Do you know if there are existing extensions for your site available? As Firefox browsers become more popular, you may want to consider creating your own extensions. It could be as easy as providing similar functionality to some of your open APIs.