As the creator of one such site dropped into an old thread today, and some sites seem to be no more I thought it might be useful to list some of the sites we know about.
There is nothing to say that you can’t just save the information anywhere and provide a URL in NDEF on your chip. In fact most of these look like that is what they do. I have no experience of any of these, but these are the ones that I could find that are currently active. This has been arranged in alphabetical order of domain name so as to not show any preference.
As I get time I will create a post showing you how to do the same sort of thing without using any of these services.