My unanswered tab looks like this, with favorite tags highlighted and ignored tags hidden:
But on the mobile site the tags have no effect on the Unanswered tab:
This appears to be a bug, because the tags do have the intended effect on the Questions tab of the mobile site. I first noticed this in mobile Opera on Android; the screenshots are from Chrome 23 on Windows 7; same happens in Firefox. The issue does not appear to be browser-dependent.