Short answer: Adobe Presenter is a tool for creating the content. Once content is created it is typically deployed on a LMS which controls the access to the content, learner registration, learner tracking, etc.
Slightly longer answer, below. Hope you find this useful as well :-)
Basically it has two parts to it - a plugin to PowerPoint and a video creation tool.
The Presenter plugin helps you to take advantage of your skills in PowerPoint and existing content that you may already have, and embellish it with your voice narration, video, interactive widgets and quizzes, scenario-based-learning interactions etc. Once you create the content you would typically publish it in Flash format and/or HTML5 format and deploy the generated output on a Learning Management System or even a web server. It is usually the LMS (or some web application) that would handle things like registration of the learners (or the intended audience) and control the access to the published content. You can check out adobeknowhow.com for this free tutorial on Adobe Presenter 11
The video creator is called Presenter Video Express (It comes along with Presenter, but since Presenter 11 you can also purchase this as a standalone product that runs on Windows/Mac). This is a desktop tool which helps user capture himself and what's one the screen (something that he could be demonstrating or presenting to) simultaneously and allows the user to mix the two streams, do various kinds of video editing, add annotations and in-video quizzes, embellish the video by replacing your background or by using various video filters, etc. You can publish its output to a video site like YouTube/Vimeo or you could also publish it locally (as you would with Presenter plugin) and then deploy the same to any LMS or web server. Here is a sample output created using Adobe Presenter Video Express 11
and here is a free tutorial that you may find helpful.
And if you are looking for an LMS, you may want to check out Adobe Captivate Prime - Learning Management System