I note that the do not mention GDPR anywhere on the homepage. This reads to me like "our business model is no longer viable" or "income is less than expenditure".
* Over the last twelve months we have been carrying out a complete technical review of the infrastructure and software we use to serve Wikispaces users. As part of the review, it has become apparent that the required investment to bring the infrastructure and code in line with modern standards is very substantial.
If I’m not mistaken, it applies to all persons in the EU (not « living there », or « citizen », literally everyone one currently « in » the EU).
So this is totally possible.
Unless you are Facebook or Google or Amazon or Microsoft (etc), most reasonably responsible companies will already be very close to GDPR compliance. The regulations really are not too onerous.
"Don't be evil" might cover it ...
Websites offer services to all countries by default; all websites are subject to GDPR, regardless of where their owners live, unless they do something like GeoIP restrictions to exclude EU citizens.
We live in such a distributed world that these local constraints are just wishes (and consultancy opportunities).
I am from the EU and love my privacy but I am also realistic.