I’ve got a similar problem scheduled and my favorite concept so far is this:
- add a custom taxonomy ‘archive’, containing userid’s as terms
- add an ‘archived’ button on each post, adding the user id to the terms and associating the post
You can then use all the taxonomy goodness to only show non-archived posts and create archive pages for each individual user…and combine it with other taxonomies.
I’ll do this as a plugin, when the time comes, but it will be a while.