Yes, I'm being facetious post Museums & the Web, but this looks like an area of tremendous opportunity if you haven't embraced it yet.
Web site Search utility is often under-realized. However, it's probably the one feature on a museum website that offers your on-line visitors the closest thing to an in-house experience.
Major art museums are out in front on this- at the conference it was noted that MOMA has figured it out. Especially with their Collections Browser. It's a bit buried, but it's a cool utility. In reviewing it, Nate Solas of the Walker stated that people like being able to search in different ways and get results in meaningful ways: "Concept Browsing is a great way to surface deep content and provide a sense of fun and discovery vs. straight up Search".
Expanding the backend behind Search and Browse on your website, and reframing it on the visitor experience end makes a lot of sense from a practical to an educational and finally, a cohesive branding perspective. It's about expanding access- to even things you can't show at the moment (or ever).
The SFMOMA does a great job of making this clear with their "Explore Modern Art" being at the top of their main navigation. My wee gripe being it's not blindingly clear what ArtScope is, and "Explore Our Collection" is a bit buried. I'm averse to feeling like an outsider especially at a modern art museum.