What is the Queue Suite?
The Queue Suite is a queue processing daemon for Frontier (at least version 5) and Radio.
A queue daemon processes items one at a time, in the order in which they are received. This is also known as a First In First Out Processing System.
The alternative to queues are stacks, which are Last In First Out. UserTalk has had easy access to stacks for a long time (though not a stack-processing daemon) via builtins.stack.
Queues are a great way to off-load lengthy tasks from any process which deals with users, to improve the perceived performance of an application.
For example, when a new message is submitted to a discussion group, it must be indexed for the search engine. If you index it immediately, the user must wait for the indexing to complete before a web page is returned. If the page is long enough, that could easily take a few seconds. If you instead put an "indexing request" into a queue, you can return the web page to the user immediately, and let a separate thread deal with indexing the message.
Another advantage to queues is that they are single-threaded, which eliminates many of the race-conditions faced in multi-threaded applications.