Tuning applications to the needs of a niche audience is a trickier proposition. As we discussed in Chapter 2, search expertise and domain expertise influence information-seeking behavior more than demographics. That said, there are a growing number of audience-specific search engines. In China, there's a "Baidu for Kids" and a "Baidu Elderly Search." The latter features large fonts, fewer graphics, clicks over text entry, and an emphasis on topics of interest to retirees. In Israel, a kosher version of Google called Koogle is optimized for Hebrew-speaking Orthodox Jews. Its index omits sexually explicit and religiously objectionable material. Plus, it excludes all content posted on the Jewish Sabbath, and if users try to sneak in a search on Saturday, Koogle crashes.[16]
One application that's fun to explore is the International Children's Digital Library. Its visual faceted navigation model lets children search for award-winning books with red covers and imaginary characters, for example. The Library's interface and facet selection are wonderfully creative and may inspire novel ideas in disparate contexts.
Some applications are designed for professional communities. For instance, ChemSpider is a search engine for chemists. By taking domain expertise for granted, its designers are free to focus on powerful options that include searching by chemical structure, identifier, elements, and properties.
When developing a specialized application like ChemSpider, it would be a mistake to assume that chemists can search proficiently. We mustn't conflate domain knowledge and search expertise. Whether designing for toddlers or physicists, we'd do well to heed that amazing engine of discovery known as Albert Einstein: "Everything should be made as simple as possible, but not simpler."