WHOIS will not be permanently offline, it will be temporarily offline while the ICANN and others work out how to give access to people who have legitimate interest in the data, ie people looking for a legal contact, sysadmins looking to notify someone, registrars themselves, etc.
I don't think the US patent database will go offline, the EU one might hide personal information like name and address unless you request access under legitimate interest.
> how to give access to people who have legitimate interest in the data, ie people looking for a legal contact, sysadmins looking to notify someone, registrars themselves, etc.
That is, anyone but the public. Oh, EU, you've done it again.
Not a lawyer, but I don't think it will affect these kinds of sites. The personal information collected in patents is collected due to government regulation. This is one of the lawful bases for using the data. The data is public information (as a result of that regulation). Affected people will have to be notified when creating a patent that their information will be used in that way -- something I think patent offices already do.
There are lots things that fall under that category, but I haven't really looked into it deeply because in my work we don't have any data collected due to government regulations.
In fact, IBM and Microsoft run this one, which is a global database. Article: https://www.zdnet.com/article/microsoft-ibm-arm-back-open-pa... Site: http://oropo.net/
So my question, is if Whois had to take their site offline due to GDPR, then will things like this go offline?
My concern is that GDPR will have a chilling effect not just on free speech, but on open information of many kinds.
PS - for reference, here is a good overview of the issues that an open patent database helps solve: http://oropo.net/oropo_report_20150615.pdf