'SeaMonkey' is Mozilla's product, formerly called 'Mozilla Application Suite'.
This is a community project, which includes many features from standalone programs or Firefox extensions. In reality, Mozilla says that the SeaMonkey's browser functionality is powered by the same engine that is implemented in Firefox 2. The Acid2 test agrees.
Even if the application has the Firefox 2 engine, it doesn't have the same extensions support. Just a few extensions are compatible with SeaMonkey, because Mozilla's attention is directed to Firefox and Thunderbird.
The application has built-in email support. The email engine is the same engine used by Thunderbird. However, it lacks the support for RSS feeds, but it has a build-in wizard that automatically sets up Gmail accounts via the POP 3 and the IMAP 4 protocols. You can also do that manually, but you need to know the settings required by the Gmail servers. This wizard is a time saver.
SeaMonkey has a built-in IRC client too. In reality, it's a Firefox extension, called Chatzilla, that is included in this package.
The application also has an address book manager. You can add/remove contacts, change the contact's details, etc. When you send an email for the first time, that address is automatically collected and placed into the address book manager.
The application also includes a tool that usually isn't available in this kind of applications. It includes a HTML editor. The HTML editor interface is split into normal type of Web page editing, HTML tags editing, HTML source editing, and the preview of the Web page that you are working on.
Another interesting feature is a small button that's available at the bottom of the navigator window, on the right side. This button allows you to switch easily between online and offline mode. This feature is available in Firefox too, but you can only find it in the 'File' menu.
Pluses: It has built in the functionality of many standalone programs and of Firefox/Thunderbird extensions. It's highly customizable.
Drawbacks / flaws: The rendering engine fails the W3C's Acid2 test. The interface could be a little more flexible, like Firefox's customization of the navigator toolbar. The interface looks like a UI from the early computer years. I thing the Neolithic age is gone, so it's time for some work to be done there.
In conclusion: With so many built-in features, this program looks more like a Opera browser with Mozilla's extension support and some extra tools. It doesn't have the same support for Web standards, as Opera does. However, the future versions of Gecko, the Mozilla's rendering engine, will bring the desired support.
version reviewed: 1.1