I have several subdomains on one of my domains and one of them was penalized by Google. My question is: When Google penalizes one subdomain (e.g. website1.mydomain.com), does the penalization apply to all subdomains of this domain? (e.g. website2.mydomain.com)
i think for google they are two separate domains.., so penalization doesn't effects to all of your other sub-domains..,
well I would say that it really depends on several factors. Like why the domain1 is penalized and how are these two domains related with each other. For example if your domain1 is doing some shady things like spamming, text link selling, hiding text, or anything that is against the Google's guidelines then your whole domain can be penalized. Or in some cases your domain2 can escape the penalty if they are not interlinked with each other. But if you are penalized for things like low quality content or for not using original or unique content then I think your domain2 will be safe if its not doing the same thing.