I was wondering if it's possible to set an album or a photo up such that an unregistered user can add and/or edit tags? I couldn't find this anywhere. Preferrably I'd like to have as much control over this as I do with comments, so that I can add a captcha or other kinds of spam prevention to the tags.

This is something that would have to be done through custom coding. All the tools are there but disabled when the user is not logged in. You would have to figure out how to enable them under the controls you want.

I see. That's problematic, of course, since I'd have to integrate whatever moderation features I need myself. Basically, what I would like to see is to have tags act pretty much exactly the same as comments for non-registered users. I guess I could take a look if I could reuse the code for the comment system or something, but it's probably not a simple tweak.

Since I just extended the tags extended the tags for Zenpage pages and articles in the svn, there are three functions involved in the tags inline editing:

template-functions.php: printTags() which calls template-functions.php: printEditable() which calls for the actual processing functions-controller.php:editInPlace_handle_request().

You probably might need to make custom versions of some or all of these functions.