One way to increase user’s trust in your search engine is to give hints about how it works. When a search engine doesn’t work, the wrong results can be mysterious. That mystery leads to mistrust and to some interesting folklore about search engine algorithms.

Why is Australian radio associated with Disney? Well, because the engine thought that the Australian Broadcasting Corporation (ABC) was the same as the ABC that is part of Disney. With no explanation, that looks stupid, but with “ABC” highlighted, it is a reasonable mistake. That extra information makes the search engine more trusted.

Snippets: These days, we expect search engines to show passages from the matched documents and to highlight the matching words. Why is that important? Because it shows what the engine matched in that document and helps explain why it appears in the results. It eliminates the mystery so the user can say, “Oh you silly engine, that is the wrong ABC!”

Because you liked: At Netflix, the recommendations are introduced with an explanation. For our account, it looks like this today, “The following movies were chosen based on your interest in: Man with the Movie Camera, Gladiator, Harvey.” Without that hint, I would be genuinely confused by recommendations including Steamboat Bill, Jr. and The Last Samurai.

Group by Topic: Showing related topics is helpful, but a topic name is usually not enough information for people to trust the link. Instead, show the topic and the first two or three documents in that topic. This is especially useful when the user’s query doesn’t match up with the way the topics are organized. A search for “linux” could match press releases, products, knowledge base, and so on. Show the first few matches in each of those areas and the contents are much more clear.

Google, Yahoo, and MSN cannot reveal their algorithms, but you can (unless you use Google for your site search, oops). The WWW engines must defend against spammers taking advantage of loopholes in their scores. If you own your own content and your own search engine, you can reveal as much as you want. Just don’t make it all about the engine, the users are there for the content.