When viewing questions in one of tags I consider interesting, using URL like
http://stackoverflow.com/questions/tagged/<tag>, and I have
<tag> among "Interesting tags", all questions are marked using "interesting tag" style... which result in strange looking page. In my opinion when viewing questions tagged with given tag, this tag should be temporarily removed (for the purpose of displaying given view) from "interesting" / "ignored" tags list.
Having all questions with yellow background looks silly.
The idea of highlighting is, I think, to be able to distinguish a few questions (those with "interesting" tags) among other questions (those without). Note that before today (19-07-2009) the behavior was different; perhaps there simply wasn't any syntax highlighting in 'view by tag' aka 'questions/tagged' view...
The revised idea is to support highlighting "interesting" / "ignored" tags also in
tagged/ view, but exclude currently viewed tag from the list of tags that highlight. This way one would be able to see other interesting tags (or other ignored tags) in
tagged/ view for some interesting tag.