Since launch our background knowledge boxes have seen heavy usage. The background knowledge boxes appear at the top of the search results and link to textbook style entries (e.g. eMedicine). The idea is that they help give some contextual links to the main research articles.
One idea we’ve got is to allow users to nominate references/links and, in a way, adopt a keyword. This is still not likely to be properly rolled out, although we did receive a suggestion for the osteoporosis entry and have added a link to the WHO FRAX fracture risk assessment tool. On one level this is a small step, but for me it carries a certain significance around future possibilities!