There are thousands of iPhone apps on the market but if you use Apple as your main source for learning about these applications you are limited to what Apple lets you know about. In addition, some are not thrilled with the web and iTunes interface and are looking for alternatives.
Moreover, users looking for that specific application in a haystack could search endlessly without success. This is because Apple has the ability to restrict applications from getting into its App Store for a variety of reasons. One application, Podcaster has been restricted because of iTunes overlap — but by many accounts it was superior in some ways to iTunes.
As an iPhone user you may want to know about all applications you could potentially download for your phone and alse see user reviews and other article links to the these apps.
This is where Apptism comes in. It is a site which allows you to view over four thousand iPhone applications with reviews and more. It is a nice alternative to the App Store and it will be interesting to see if Apple tries to shut the site down somehow.