Perhaps it would be better to say that they deserve thanks, but you also have to take into account the time in which these donations happened - which was mostly at a time when the price of BTC was very low, and people were mining with their computers and for each block received as much as 50 BTC reward.

Given that you posted a link to the list of donors and that you have a tool like BPIP you only need a little time and you can check for each donor when he was last active.