Why does the world need Media Album -- aren't there already dozens of web-based photo applications similar to Media Album?

There certainly are! I counted up 20 or so within an hour of casual web-surfing recently. Media Album actually began life in September 2002. After frustration over not being able to easily share photos with family and friends I looked around for a free solution. None of the solutions at the time fit my needs exactly, thus Media Album was born. You should evaluate your photo/movie sharing needs and pick a web-based application that serves you well! That being said, here are some of the features which differentiate Media Album from other similar applications:

Java web application
Most other web photo sharing applications are written in PHP. If you don't run PHP on your web server then you're out of luck. Media Album is a Java web application, however. In a most basic setting you only need two things to run Media Album (not counting a database): a Java application server and Media Album. There are several high-quality and completely free Java application servers available like Apache Tomcat or JBoss. You don't need any other libraries like GD installed, and you don't even need to have a separate web server.
High performance that won't take down your server
Media Album is designed to handle thousands upon thousands of media items. Since it scales the items and compresses them on the fly according to user preferences it can also take up a great deal of your server's processing capabilities. Media Album can safely respond to many simultaneous requests without overloading your server, however, by making use of work schedulers and queues. Sounds fancier than it might actually be, but just know that when 50 of your closest friends attempt to download your latest album of 1,000 photos, all scaled from 4000x2000 to 640x480 and rotated as necessary and re-compressed, your server will graciously oblige without resorting to consuming all your memory and crashing your hard drive. You can even adjust how much processing Media Album will attempt to do at once so you tune Media Album to run on your old original iMac on up to your personal X-processor mega server.
Insanely customizable
Did I say insanely? Yes, in fact it is true. Media Album has been designed with many different viewing mediums in mind, from viewing albums over your cell phone to viewing them as PDF documents. For the most part people will view your albums using their favorite web browser, however, so that is where Media Album concentrates right now. But even within the world of HTML much flexibility is granted to Media Album themes. Media Album themes are not simple templates, they rely on XSLT to transform XML data into whatever sort of form you'd like. Media Album also allows you to manage your own themes and install them without stopping/starting the application.
Time zone support
Have you ever travelled to, say, Hawaii from your hometown of, say, New York, and taken photos with your digital camera? Perhaps you wondered after you returned to New York why those photos taken during breakfast on the beach say they were taken at 4 AM? At least you don't remember getting up that early... With Media Album you get to specify your camera's time zone, and then you can specify the time zone individual items were created in. Thus those 4 AM photos would appear as 9 AM for you. Mystery solved!
Watch for updates
You can elect to watch entire Media Album libraries or individual albums for updates. When new items are added that Media Album will send you a friendly email telling you so.
Email photos
You can email photos to your friends, either as attachments in the email itself or in the form of a URL link.
Emblazon your images with a watermark of your design so that no matter what chain email your photo travels with, it will always carry your personal signature.
Custom meta data
Media Album lets you assign types to media, which allow you to add useful meta data to items. For example the custom types include a book type, which allows you to add an author and publisher to the media. In this way you can upload a scanned image of a book cover and also save the author and publisher as meta data fields. These meta data fields can then be searched, allowing you to, for example, find all books you have by a specific author.
Download albums
Media Album lets you download entire albums as a zip file. You can choose to download items scaled to your view settings (eg. 640 x 480) or the original media items. Either way Media Album creates the zip for you on the fly.
Rate your media items from 1-10. You can then browse all your items according to your ratings. If you are logged in to Media Album you can also rate other users' media items. You can then browse their items according to your ratings. You can also browse other users' media items by their owner's ratings. Or you can browse anyone's media items by the average of all ratings. Any way you slice it, ratings give you great flexibility to keep track of your favorites, and other people's favorites.
Media Album provides you with a shopping cart-like holding area for media items you come across while browsing, called a lightbox. While browsing if something strikes your fancy you can add it to your lightbox. Then from your lightbox you can do things to those items in it, like email or download them. For example, maybe you want only 10 of the 99 photos in somebody's album. With the lightbox feature you simply add those 10 to your lightbox then download them all as a zip file, saving you quite a bit in download time if you're on a slow internet connection.
You can assign quotas to users on your Media Album system to limit the number of items they can upload.