The file synchronization and hosting service Dropbox recently crushed the 100 million user mark, which is fairly impressive if you consider that all "big" Internet players are also offering synchronization services of their own. Anyway, the company is not resting and has already made quite a few acquisitions in the recent past that will improve the service further.
Not all services have been fully integrated into Dropbox at the time of writing, but it is clear that Dropbox wants to improve its service in regards to file accessibility and features in general.
Dropbox users can work with clients that need to be installed on desktop systems or mobile devices, or on the Dropbox website directly. If you have browsed your files on the website before, you know that it is not really easy to navigate. The core reason for that is that you can only display one folder at a time in the application.
When you click on a folder in root, you only see the contents of that folder on the website. If you want to switch to a different folder under root, you have to go back first before you can make the switch.
Dropbox Plus is a userscript that works in Firefox, and probably in other web browsers supporting user scripts as well. Firefox users need Greasemonkey or a comparable add-on before they can install the script in their web browser.
The main new feature that Dropbox Plus adds to the Dropbox website is a new tree style view of folders in the sidebar. It works independently from the main list of folders that you can browse on the website.
The idea here is to provide you with the means to quickly jump to another folder on Dropbox without having to go back to the root directly first to do so.
To do so, simply click on any folder listed in the sidebar. You are automatically taken to that folder so that its contents are displayed on the right afterwards.
You save at least one click, maybe more, and some time, when you are using the script.
If you access files regularly on the main Dropbox website, you may find the script helpful as it may speed up the browsing of folders on it. The tree style folder view is not interfering with any functionality or placement of links on Dropbox, as it is added underneath all official sidebar links on the website.