Probably. As long as it's easily hand-editable it should work fine. I suggested XML because of the plethora of editing tools available and it's good design vis a vis escape-needing characters. A colon-delimited text file or some such would work too, as long as we handle escaping of real colons in the string.
3. .po files
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The idea is to not use PO files and t() in the first place for the help text, because for larger text strings they're much slower than a simple database hit.
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I don't know, as I've never used PO files myself. :-) My only use for translation so far personally has been to customize the built-in text for a client by creating a fake locale and "translating" just a few strings to have more app-specific text.
Translation people, any thoughts here?
If you only need to have key->value pairs, there is no reason to abandon PO files. If you try to contact some real people doing translation, you will notice that 'easily hand editable with XML editors' is not easy enough. Goba