Unfortunately, those who search for expired domains, too often (not always obviously) do not care about some vital parameters that, if neglected, could determine a penalty for all linked sites. of IP classes or other checks useful for verifying whether the domain has been banned in the past. As you can understand if a domain brings with it good links it will be the object of the attention of many, including spammers.
And do you know what happens if by mistake one taiwan phone data previously used for spam is resurrected during its second life? As you can imagine, nothing good. Another vital check among those usually ignored is the verification of the ban by Google Adsense. Many expired domains, in fact, are abandoned precisely because they are banned by Google Adsense. You understand that the reputation of a site of this type can only undermine the authority of those who find themselves receiving incoming links from the latter.
.. Another thing that I would never want (and, trust me, neither would you) is for my portal to take links from a site that in the past sold beautiful Chinese rubber dildos. Do you really think so? Well, it often happens that you discover that an old domain, apparently perfect, in the past has been hacked or, even worse, used - here we go again - to spam, in this case hosting, between dildos and viagra, the worst things.