right well from my point of view it's not a knowlege issue but a website design issue.
For one thing. Your buttons only work if you DON'T click on the icons.
So on a drop down menu clicking on the arrow does nothing but clicking on the words does.
The opposite of almost every website I've ever been on.

I suspect many people will click repeatedly on the arrow for picking a technology - nothing happens and just give up.

Other than that it's a well laid out site, plenty of information. Just weird buttons :-)