Also, I'd suggest letting people set up tag filters without accounts. Even if they don't persist beyond a single visit, it allows users to see just how useful t

Also, I'd suggest letting people set up tag filters without accounts. Even if they don't persist beyond a single visit, it allows users to see just how useful this tag concept is without any commitment, making them more likely to use the site. They'll also be more likely to sign up for an account since they already spent some time making a filter and might want to save it.