Outliner icons explanation

Hi fellow blenderers.

for a long time I’ve been struggling with the outliner and haven’t found an article that clearly explains what every icon in the outliner means.

I know there are the hide\show icons to the right, and I know that some icons mean mesh\curve\empty\light\camera\etc.
but there are other icons, like vertex groups, links, data blocks, bones… that unless you’re really familiar with the program you wont know what they are, or worse how and why they effect your scene.

I wonder if there’s any written document on the matter?