Well, whoever the owner is - he/she seems to be providing this service for free. Also if you click on any of the links, in the dialog that opens up, there is a website link at the bottom. I've had little trouble finding my way to the sign up pages.

If we spread the word around about the website, then perhaps devs of new altcoins will voluntarily submit airdrop info to the owner - making the owner's job of collecting the information much easier in the future. We shall see how this turns out. At the moment I think, it's probably a lot of hard work for the owner to collect all the information and keep it up to date.