We really hate ads.

And we are enthusiasts who created this site because we love the subject and love the idea of explaining difficult topics in an intuitive way.

Paying for this site is therefore something we do because we feel it's worth it.

Just like TED's slogan: Ideas worth spreading.

But if you found this site useful or it helped you learn something you struggled with and you want pitch in - this is your opportunity.

We are not begging, we never will. We don't need donations to afford bread on the table. We are OK, really. 

This is if you want to show us a gesture like "you did something good, here's some of my spare change".

And for that, we are thankful.