How about this: <tag type="author|reader|auto" rel="label|means|etc" value="label1,label2"/> which can be included anywhere in the doc and can be parsed/ign

How about this: <tag type="author|reader|auto" rel="label|means|etc" value="label1,label2"/> which can be included anywhere in the doc and can be parsed/ignored according to some browser setting, leaving the whole document intact?