YouKneeK found that Dawid Piaskowski stopped being Booklikes' "CEO and cofounder" in April 2016. I discovered that Joanna Grzelak-Piaskowska, Booklikes' other cofounder and owner, sold Booklikes in 2016 ("After selling Okazjum.pl to Bauer Media Group in 2015 and BookLikes in 2016, Joanna with her husband are already working on something new."). Considering the info about Dawid, I would guess that the sale happened sometime last month.
I've searched Google and several business and company info databases and have been unable to find anything about the new owner(s). Dawid Piaskowski is still listed as the owner of the site's domain name.
If anyone finds any other info, please let the rest of us know! At the moment, I'm most concerned about the owner's plans. If they intended to keep the site running, wouldn't they have introduced themselves? And, if they didn't intend to keep it running, what did they buy it for? All I can think that they might want is any data it has generated or collected. Which is a little worrisome.