In order to maintain my vendor neutrality, I refrain from advising software companies about their products. But that doesn't stop me from having ideas and opinions so I am starting a series of features that I would like to see. Please feel free to use them and, if you do, tell me about it! If you don't like an idea, let me know why.
Today's feature request can probably be implemented (at least primitively) as a minor customization on most content management systems.
When a visitor searches for content on the site (or arrives at the site from an external search result), the presentation tier records the keywords that he used. These keywords are then listed as options that content contributors can use to tag their content. This would allow contributors to tag content in the language of their audience. To keep things manageable, there should be a mechanism for filtering out typos and organizing the keywords. There may be some system that would allow you to group synonyms so if people search equally for "bike" and "bicycle," the contributor only has to use one of those terms and the asset is returned on both "bicycle" and "bike" searches.
The original seed for this idea occurred way back when Arjé Cahn, from Hippo, told me of an experimental feature that used the terms a contributor used to search for related images and links as keyword suggestions for the asset he was working on. This feature idea takes it one step further by using the language of the audience, rather than the contributor. Another part of the inspiration comes from the "Best Bets" strategy where you train a search engine to recommend a certain set of assets when a specific keyword is used.