Why do you need to know who donates money to whom and how much it is? Just because you don't know who donates money, doesn't mean it's not happening :-P
And it's actually not a donation. He works and you give him money. Unless Marek is a non-profit organization it is not a donation and he has to pay taxes for the money he gets (I hope he is doing this, I don't want him in jail ;-)).
Glad you decided to donate too, how much is acceptable for you?
Also, I will know no more than anyone else reading the thread, so I hope it answers your question. Now, please answer mine