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.
GDPR is going to be a tax on software for a good chunk of time, and probably a decent source of employment for engineers, as companies wake up and realize that they now have to deal with it. Unless there specifically are requirements to make deleting user data easy, or even possible, that's probably been punted on for years in most software products.
GDPR is going to be a tax on software for a good chunk of time
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.
From what I've seen, I wouldn't be too surprised if some practices make this hard for some companies. In particular, mixing customer data with company data and having a practice of tomb stoning rows.