Mozilla Suite : FAQs : Status
From MozillaZine Knowledge Base
Mozilla Suite code development and the SeaMonkey project
The 1.7 release of the Mozilla Suite is the last major release as an official Mozilla Foundation product. It will be maintained with 1.7.x version releases to fix known security problems or other critical issues but there will be no official Mozilla Suite 1.8 release. This will enable the Foundation to devote its resources to the standalone Firefox and Thunderbird applications.
Although official development has ceased, the Suite will continue to evolve as a community-led project and will receive substantial support from the Foundation. In particular, the development community will still use mozilla.org's webtools such as CVS, LXR and Bugzilla, and Foundation members have provided significant advice to the community on how to organize successful releases of a Gecko-based application suite. The project will be "driven" by members of the community who will be responsible for maintaining code, dictating the release schedule and performing QA on the final releases. More information on the organizational structure that has developed to maintain the suite and manage future releases is on the SeaMonkey homepage at wiki.mozilla.org.
Since this community-led project does not result in an official Mozilla Foundation product, it was agreed that the name and version number of the new release must change, as it is not possible to use the "Mozilla" trademark on an unofficial product. The name "SeaMonkey" was chosen, after the longtime codename of the Mozilla Suite. This new release of the application suite, based on Mozilla Suite 1.8 code, is named "SeaMonkey 1.0" and was released on January 30, 2006. Subsequently, the SeaMonkey project released SeaMonkey 1.1 in January 2007, and then developed SeaMonkey 2.0 with a final release in October 2009. 
Differences between the Mozilla Suite and SeaMonkey
Despite the name change, SeaMonkey 1.x will feel very familiar to Mozilla Suite users, but it will incorporate new features (such as roaming profile support) UI improvements and bugfixes. Some of the improvements found in SeaMonkey 1.0 as compared to Mozilla Suite 1.7.xx are listed here. Additional information can be found in the SeaMonkey release notes for each version, available through the SeaMonkey project page.
"Mozilla Suite" vs. "SeaMonkey" in Knowledge Base articles
You may find one or both names used in different articles. It is generally safe to assume that references to "Mozilla Suite" also apply to "SeaMonkey 1.x", unless otherwise noted. Articles that apply to SeaMonkey 2 will be so noted.
In some articles, especially those written for Thunderbird, there may be a note stating that the article "also applies to Mozilla Suite / SeaMonkey". This could mean that the article applies to both products (most likely) or perhaps only to SeaMonkey 1.x or 2 (e.g., due to new features in SeaMonkey that are lacking in the Mozilla Suite). Article writers often don't know the specific differences between Mozilla Suite and SeaMonkey and thus use the shorthand "Mozilla Suite / SeaMonkey" note to flag articles that might be of interest to Mozilla Suite and/or SeaMonkey users.