I had been thinking that it would be nice if the navigation on our pages did not affect the overall ranking in search engines. Particularly the AAAS search engine, which doesn't do so well when the search terms include words from the navigation. Some kind of container tag or attribute that could be used to say "don't look at this" to the search engine spiders.
Supposedly a method was floated a few years ago, but nothing came of it. In all likelihood the major search engines have already come up with methods of decreasing the weight of content that is reapeated often on an individual domain.
To put a final nail in the coffin of this idea, AAAS updated their search engine this year and it appears to do a much better job than it used to.