I am considering wearing an id plate in case of emergency/accident/what not.

Quick search suggests name + SSN + Blood type. Other infos might be some health condition. Which leaves me wondering...

My impression is that a tag should facilitate positive identification (everywhere in the world) and list emergency contacts. (Is blood type really useful?)

So... Relevant info could be:

1. Name
2. Passeport number
3. Primary emergency contact email + phone
4. Alternate contact email + phone
5. Link to emergency www page

Things you'd remove/add? Including opinions on the merit of such tags.