Wait: At this stage, Mindliner is concept software. It won't lose your data or anything but most people find it hard to use. It could still be interesting for you, if:
You start by creating an account. In the process you will also create a "data pool", this is place where Mindliner puts all the information you enter. Until the moment when you invite other useres to join your pool it will be your private space.
The web app let's you add and search for information with minimal setup. It is a good place to start and it is currently the method to use Mindliner on mobile devices. For most applications, however, it will not be a substitute for the desktop app. Please see the corresponding video tutorial for an easy start.
Once you have created your account and added, edited, or deleted a few knowlets (aka "Mindliner objects") you may want to install the desktop app (unique features for the desktop app). The current version is 2.6.20.