My friend Andy forwarded me this link: Building Fast Client-Side Searches. It's an exercise in data serialization. I especially like "store everything you need in one database text blob". This is a technique that should be used more often. Sadly they do not say which browser they were testing on. I suspect this significantly changes from engine to engine. Firefox 3.5 will get native JSON parsing which should help greatly.
Anyways, it's a good read